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From thc ANNALS AND MAG- OF NATURAL HISTORY,Ser. 10, vol. mi. p. 65, July 1935.A Synopsis of the Cichlid Fishes of Lake Nyasa.By ETHELWYNN TREWAVAS, D.Sc.THE Cichlid Fishes of Nyasa were revised in 19gby Regan(Proc. Zool. Soc. Lond. 1921), who increased the numberof described species from 38 to 84. The British Museum(Natural History) is fortunate in possessing the types of allthose species. Regan's revision was based on a collectionmade by Mr. Rodney C. Wood, from hauls brought in bynative fishermen. Dr. Regan recognized that Mr. Wood'scollection indicated the presence in the lake of a rich andvaried Cichlid fauna, and he arranged for the late Dr. CuthbertChristy to make a special expedition to the lake in 1925-26,which resulted in the very fine collection on which the presentmvision is mainly based. In the Christy Collection thef@y Cichlida is represented by about 3500 specimens.Jh. Regan had already started work on it when I joinedth staff of the Natural History Museum in 1928, and hehas kindly placed his notes at my disposal, as well as takinga ~onstmt and helpful interest in my further work.

66 Dr. Et,helwynn Trewavas onIn 1927 Ah1 * published descriptions of some new NyasaCichlitlz, part of a large collcction in the Berlin Museum.He has kindly allowed me to examine the typcs of theso inBcrlin. Nichols and LaMonte (Amer. Mus. Novit. no. 451,1931)described two species which they believed to be new, buttheir Haplochromis centropristoides is H. callipterus, and theirH. boultoni is a young specimen of H. czruleus.A revision of the genus Lethrinops, based on the Christycollection, has already been published (Trewavas, Ann. &Mag. Nat. Hist. (10) vii. 1931, p. 133-152). I have nowto add one more species to this genus, and I give a synopsisof the remaining Nyasa genera and of their species.Twenty-three genera are here recognized, of which twentyare endemic and fourteen are monotypic. Of the one hundredand se-venty-five species comprised in these genera, onehr~ndrcd and one belong to the large genus Hapbchromis.IIaplochm~tis cnllipterus is closoly related to Ii. moffati ofSouth Africa; it differs from thc other Nyasa species ofHaplochrmis in having the caudal rounded, and scaled onlyat the base. Of the remaining forms Regan has written -" In the Nyassa species the caudal fin is truncate or emarginate,and appears to be always nearly completely coveredwith small scales in the adult fish ; this feature, the prevalenceof a few distinctive types of coloration, and the absence ofevident relationship to species found elsewhere lead to theconclusion that the Nyassa species are a natural group andmay, perhaps, have evolved in the Iake from a single ancestralform." Even in young fish, although scales may be absentfrom thc central part of the caudal fin, they extend along theuppcr and lower rays ncnrly to the ond.Efforts to divide the Nyasa Haplochromis into smaller generahave been unsatisfactory. On the contrary, it has beennecessary to merge in it three previously recognized genera,as is explained below. It would be possible to take certainextreme forms and to define them as genera, but as thesewould be monotypic the main genus would not be muchdecreased. The guiding principle has been that monotypicgenera have been formed for peculiar species only whenthey are isolated, and have no obvious close relationshipwit,h a more generalized form, whereas a species such asIfaplochrmis melanonotus, which is closely related to H. semipabatus,sp. n., is left wit'hin the genus, even although thismakes its definition more difficult.Full descriptions of all the species have been written,and figures of all the new ones have been prepared, and* .sitzungsbcr. Ges. naturf. Fr. Berlin, July 1926 (1927), pp. 51-62.

the Cicl~lid Fishes of Lake Nyasa.will be published when a monograph of the African Ciolilidah

68 Dr. Ethelwynn Trewavas onChin strongly projecting ; posterior teethnot enlarged ; mouth broad. withbroad transverse bands of teeth .... 9. Genyochromis, p. 79.A. Anterior teeth long, pointed, unicuspid, directedforwards ............ 10. Labidochromis, p. 80.b. Scales on cheek, nape, and chest not vory small.Praemaxillaries not beak-like ; teeth alltricuspid (rare), or inner tricuspid andouter bicuspid, or inner tricuspid andouter with slender shafts and compressedobliquely truncate crowns, orall teeth conical, at least in fullgrowni%h, or outer bicuspid andinner simple ; vertebra? 29-35 ...... 11. Haplochromis, p. 8 1.Praemaxillaries not beak-like ; jaws withbroad bands of small, simple teethwith compressed, sharp-edged crowns ;vertebrae 31 or 32. ................. 12. Cvrematodus, p. 108.Praemaxillaries not beak-like ; jaws strong;teeth stout, incisiform, unicuspid(full-grown), or with a large middlecusp and a pair of small lateral cusps(yo.ung). in 4 or 5 well-separatedseries ; outer teeth large, forming aclose-set series of about 20 in eachjaw; vertebrae 32 ................ 13. Docimodus, p. 108.Praenlarillaries not beak-like ; jam weak,with small teeth, the outer series oflower jaw incurved posteriorly, endingimmediately behiid the inner, antiat some distance from the coronoidprocess ; vertebrae 31 or 32 ........ 14. Letkrinops, p. 109.Praemaxillariesnot beak-like ; mouth wide ;outer anterior teeth bluntly bicuspidin young; in adult teeth stout, all,except a few inner, with crowns shapedlike a grain of wheat, bluntly pointctlinwards, with B groove on the outorsurface; tooth-band of upper jawwider postero-laterally than near thosymphysis ; vertebrae 31. ........... 16. Chilotilapia, p. 110.Praemaxillaries beak-like ; teeth simple,with slender shafts and compressedcrowns, the outer obliquelytruncate and inclined towards thesymphysis ; vertebra 31 .......... 16. Hemitilapia, p. 110.Praemaxillaries beak-like ; teeth conical,spaced, the anterior enlarged ; [p. 112.vertebra 36 to 40.. ................ 17. Rhamphochromis,2. Otic region of skull and mucus-canals of hcad swollen; 31vertebra.Cheek with 2 to 4 series of scales. ....... 18. Trematocranus, p. 113.Cheek with a single series of scales or none. 19. Adonocara, p. 115.B. Third, or third and fourth vertebrae with inferior apophysos whichare short, and do not approach each other below dorsal aorta;vertebrae 16+ 18 ; teeth conical, in two series ; praemaxillariesnot beak-like ................ 20. Diplotmodon, p. 116.

the Cichlid Pishes of Lake Nyasa.C. No inferior apophyses on anterior vertebrae; prsemaxillariesproduced forwards and bonk-like ; teeth in a single series exceptanteriorly . . . . . . . . . . . . . . . . . . . . 21. Lichnochromis, p. 1 17.D. Inferior apophyses either on fourth vertebra, or on fourth onleft siclo, al)scnt or on third on right ; vertebrre 33 or 34 ;przmaxillarios forming a lnternlly compressed beak ; teethsmnall, conical, in 3 or 4 series anteriorly.22. Aristochromis, p. 117.E. Inferior apophyses on fourth or fourth and fifth vertebrae * .vertebrae 37 to 39 ; prremaxillaries not beak-like ; teeticonical, in two series, or three anteriorly in upper jaw, inlower in a single series, except anteriorly.23. Sewanochromh, p. 118.In 1920 Regan classified the African Cichlidse into two maingroups, characterized by the structure of the apophysisthat supports the upper pharyngeals t. Except Tilupia,the Nyasa genera belong to the Haplochromis group, in whichthe apophysis is formed by the parasphenoid in the middleand the basioccipital at the sides. In 1921 Regan placedtwo of these in the Tilapia group, Corematodus and Hemitilapia.In Corematodus he was misled by the striking superficialresemblance between 0. shiranus and Tilupia squamipinnis,but a second species with an entirely different colour-patternhas now been found, and several specimens of both show thetypical Haplochromis apophysis. Hemitilapia was misplacedon the evidence of a damaged skeleton.In the genera Otopharynx and Chilotilapia the apophysiswas described as being formed by parasphenoid and prootio.In 0. auromarginatus the pharyngeals are weak, and theapophysis, correspqndingly small, is formed mainly fromthe parasphenoid, but at the .postero-lateral corner thebasioccipital contributes to the apophysis a process whichusually reaches the level of the articular surface, and mayexpand to occupy as much as ) of each of the pair of facets.As in Haplochromis, the edge of the prootic may at one pointrise nearly or quite to the level of the facet, but it neverexpands to form an important part of it. The genus Otopharynxmust, therefore, in the present state of our knowledge,be merged in Haplochromis. 0. selenurus Regan has a typical* This applies to S. thudergi end S. angustioeps. An example ofS. macrocephalus has the apophyses on the third vertebra as in Haplochromis.t .This character may be easily investigated, even in an uniquespecimen, by cutting the mmles connecting the whole branchialskeleton, including the pharyngeal bones, to skull, vertebrae. and shouldergirdle,leaving the branchial apparatus attached only to the base of thehyoid arch, then removing the synovial ruombrane from the apophysis.

70 Dr. Ethelwynn Trewavas onHaplochromis apophysis, and appears to be related to Cyrtocaramoorii, which is also here included in Haplochrmis (seebelow). Chilotihpia belongs to the Haplochromis group,but its peculiar dentition entitles it to generic rank.There is considerable variation, both individual and specific,in the degree to which the basioccipital participates in thearticular facet, but the apophysis is sharply differentiatedfrom the Tilapia type, in which not only the facet, but thewhole apophysis, is formed by the parasphenoid, buttressedlaterally by t'he prootic. The only Nyasa species in whichthe prootic takes any appreciable share in the facet is Haplochromisplawdon, with massive pharyngeal bones.Astatotilapia Pellegrin was recognized by Regan (1921)for A. calliptera of Nyasa and its allies ; but he has sincegiven up the attempt to maintain this genus, which is nowincluded in Haplochromis.Cyrtocara was established by Boulenger for C. moorii,and was held to be distinguished by its dentition and bythe entire edge of the spinous dorsal. C. moorii is furtherdistinguished by the presence of a dermal hump in the frontalregion. Regan added C. annectens, which is without the bumpand has a dentition intermediate between a type comnonin Haplochromis and that of C. moorii. Regan also includedin this genus Haplochromis venustus Boulenger, on the groundof its possessing an entire edge to the spinous dorsal. Thetypes of H. venustus are full-grown males ; females of thesame species have been described, under the name of Haplochromissimulans, by Regan (1921), who pointed out theresemblance to H. venustus. The straight edge of the dorsalfin is in this species a character of larger males, as it is insome species of Lethrinops. In Cyrtocara moorii andC. annectens large specimens, probably of both scxes, havea spinous dorsal with an even edge, but the young havelappets ; it has been thought best to include these two speciesin Haplochromis.A few of the genera derived from Haplochromis differfrom it in the degree of development of the inferior vertebralapophyses and in the vertebrae on which they are found.Departure from the Haplochromis condition of this featureseems to be accompanied by instability, so that genericdefinitions involving these apophyses must not be regardedas rigid when based on one or two specimens only. Whenthe anatomy becomes better known it is not improbablethat differences in the inferior apophyses will be found to beassociated with differences in the shape, size, or positionof the air-bladder, which is firmly attached to them. Fisheshaving the apophyses on the fourth or fifth vertebra are

the Cichlid Fishes of Lake Nyasa. 71usually elongate in form. In the very elongate Rhamphochromis,however, the apophyses originate on the third vertebra,although they a,re directed backwards to meet and end belowthe fourth. Individual variation in genera with the Haplochrornistype of apophyses is slight ; among the specimensexamined, one of four specimens of H. chrysonotus has a pairof inferior apophyses on the sccond vertebra and a singleone on the right side of the third, a specimen of Labidoch.romisvellicans has the left apophysis on the third vertebra, theright on the fourth.Genera 2 to 10, from Pseudotropheus to Labidochromis, aremore closely related to each other than to any other genus,although it is very difficult to find an absolute character todistinguish them. The small scales on cheek and nape arevery characteristic, but some specimens, of P. mvemfasciatusand P. livingstonii, for example, have no more than areoften met with in Haplochromis. High numbers of dorsalspines and low numbers of soft dorsal and anal rays areusual. The vertebral count 15+16, found in 6 of 13 specimensin this group, is found in only 1 of 45 specimens ofNyasa Haplochromis, or 1 of 23 of the Nyasa Haplochromiswith the same total number of vertebrs (30 or 31) as thesesmall fishes. The number 14+17 is found in 5 of the 13specimens of the Pseudotropheus group and in 10 of the23 Haplochromis. 14+16 is found in two of each. Theremaining 10 Haplochromis have 13+17(3) or 13+18 (7).Features of the colour-pattern, which occur in some specimensof most, but not all, species of genera 2 to 10 and are rarelymet with elsewhere, are the very broad black submarginalband of the dorsal fin, and the posterior position and intensityof one or more bright spots on the anal fin in males." Total length " includes the caudal fin." Thc length - " is the standard length, from snout to baseof caudal." Length of snout " is measured from the vertical from theanterior edge of the eye to the level of the tip of the snout,along a line parallel to the longitudinal axis of the body." Length of head " is measured along the same line.'I Depth of prsorbital " is measured from about the middleof the orbital rim of the prsorbital bone along a line whichcontinues the radius of the eye at this point. This lineapproximately bisects the bone." Interorbital width " is the narrowest width of the roofingpart of the frontal bones, between the eyes.

service of Carrier 1 using a special port number), and Other(all other port numbers). They contribute to 78.8%, 15.1%,0.2%, and 5.9% of the total traffic volume, respectively.We use a threshold of 10 sec of idle time to decide thata connection has terminated. Changing this value does notqualitatively affect the simulation results.For simplicity, we assume that there are four applications,each involving one traffic type, running on smartphones. ForWeb, Email, and Sync applications, a transfer is defined asconsecutive connections of the same traffic type whose interconnectiontime (the interval between the last packet of oneconnection and the first packet of the next connection) isless than 1 sec. Note that a transfer may consist of multipleconnections and connections may overlap (e.g., concurrentconnections supported by smartphone browsers). Atthe end of each transfer, each application independently callsTerminateTail with probability of z, which quantifies theapplicability of TOP, to perform binary predictions (whetherITT is greater than TT, see §VI-B) with accuracy of w.In other words, the probabilities of a correct prediction, anincorrect prediction, and no prediction (TerminateTail isnot invoked) are zw, z(1−w), and 1−z, respectively. Sincebinary predictions are performed, each application uses an ITTof 60 sec if the ITT is predicted to be greater than TT. Varyingthis from 30 sec to infinity, or using the exact prediction valueof ITT changes the results in Figure 7 by no more than 0.01.We assume that the “Other” application is unaware of TOP.Figure 7 plots the impact of TOP on ∆E, ∆S, ∆D T , and∆D by varying w and z for Carrier 1. In each plot, thez = 0 curve is a horizontal line at y = 0 correspondingto the comparison baseline i.e., the default case where TOPor fast dormancy is not used. Figure 7 clearly shows that,increasing z, the applicability of TOP, brings more savingsat the cost of increasing the state promotion delay. On theother hand, increasing w, the prediction accuracy, not onlybenefits resource savings but also reduces the state promotionoverhead. Under the case where z = 0.8 and w = 90%,TOP saves the overall radio energy E, the DCH tail timeD T , and the total DCH time D by 17.4%, 55.5%, and 11.7%,respectively, with the state promotion delay S increasing by14.8%. The results for Carrier 2 show similar trends. Underthe condition of z = 0.8 and w = 90%, TOP can save E,D T , and D by 14.9%, 60.1%, and 14.3%, respectively withS increasing by 9.0%.We compare TOP with other schemes for saving the tailtime. In each plot of Figure 8, the X axis is the state promotiondelay ∆S, and the Y axis corresponds to saved resources(∆E, ∆D T , or ∆D) for Carrier 2. A more downward orleftward curve indicates a better saving scheme since given afixed ∆S, we prefer a more negative value of ∆E, ∆D T , or∆D indicating higher resource savings. Each plot of Figure 8contains four curves. The “TOP” curve corresponds to usingTOP with w = 80% and z being varied from 0.5 to 1.0.The “FD” (fast dormancy) curve is generated using the sameparameters, but in the “FD” scheme, applications use fastdormancy without being scheduled by TOP. In other words,an application (Web, Email, or Sync) sends a T messagewhenever its predicted ITT is greater than TT. The “timer”curve corresponds to a strategy of proportionally decreasingα and β timers that affect all sessions in the trace.The “TE” curve denotes employing TailEnder [6] to save energyand radio resources. As described in §I, for delay-tolerantapplications, their data transfers can be delayed and batchedto reduce the tail time. TailEnder is a scheduling algorithmthat schedules transfers to minimize the energy consumptionwhile meeting user-specified deadlines by delaying transfersand transmitting them together. The TailEnder algorithm wasimplemented in our simulator using the default parametersdescribed in [6]. We apply TailEnder on all Email and Synctransfers and vary the deadline (the maximally tolerated delay)from 0 to 5 minutes. A longer deadline can potentially savemore resources but a user has to wait for longer time.We discuss the results in Figure 8. TOP outperforms fastdormancy(FD), whose curve lies on the right of the “TOP”curve. To achieve the same savings in D, E, and D T , thestate promotion delay of TOP is always less than that ofFD by 10% of the overall promotion delay in the defaultscheme. Further, reducing inactivity timers incurs additionalstate promotions, overwhelming the savings of D and E. Thefundamental reason for this is the static nature of the inactivitytimer paradigm where all packets experience the same timeoutperiod. We also notice that TailEnder can reduce the overallstate promotion delay (as indicated by the negative∆S values)due to its batching strategy. However, its applicability is verylimited, yielding much less savings, and it incurs additionalwaiting time for users. The comparison results for Carrier 1is qualitatively similar, implying that invoking fast dormancywith a reasonable prediction accuracy (around 80%) surpassesthe traditional approach of tuning inactivity timers in balancingthe tradeoff, and TOP’s coordination algorithm effectivelyreduces the state promotion overhead caused by concurrentnetwork activities.B. Evaluation using locally collected tracesWe perform case studies of two applications (Pandorastreaming and Web browsing) using traces locally collectedfrom an Android G2 phone using Carrier 2’s UMTS network.We investigate each application separately without injectingconcurrent traffic, then apply the coordination algorithm onthe aggregated traffic of both applications.1) Pandora radio streaming: Pandora [1] is an Internetradio application. We collected a 30-min trace using Tcpdumpby logging onto one author’s Pandora account, selecting a predefinedradio station, then listening to seven tracks (songs).By analyzing the trace, we found that the Pandora trafficconsists of two components: the audio/control traffic and theadvertisement traffic. Before a track is over, the content ofthe next track is transferred in one burst utilizing the maximalbandwidth. Then at the exact moment of switching to the nexttrack, a small traffic burst of control messages is generated.The second component is periodical advertisement traffic froman Amazon EC2 server for every one minute. Each such burstcan trigger an IDLE→DCH promotion.

the Cichlid Fishes of Lake Nyma.bars, if present, very faint ; interorbital width 3 to 44 inlength of head, diameter of eye 34 to 44 (in specimens of70 to 165 mm.) ; D. XVI-XVIII 9-11 ; A. I11 7-9 ;caudal truncate .............. 4. williamsi.2. Tooth-band of lower jaw transverse ; body uniformly brownish,or with traces of vertical bars and of two longitudinalbands; interorbital width 2$ to 33 in length of head,diameter of eye 34 to 4 (in specimens of 90 to 140 mm.) ;D. XVII-XVIII 9-10 ; A. I11 7-9 . 6. Iucerna.B. Dcpth of body 3 to 33 in the length ; tooth-band of lower jawrounded.I. Colour uniformly dark ; interorbital width 4# in length ofhead ; D. XVIII 9 ; A. I11 8 .... 6. fuscus.2. A longitudinal stripe along middle of side, another above upperlateral line, black on gold in female, gold on dark brownishin male ; felnale with a black submarginal band on dorsalfin, male with dorsal pale; interorbital width 34 to 4 inlength of head ; D. XVIIJXIX 8-9. 7. auratus.11. Snout shorter than or as long as diameter of eye.A. Upper profile gently sloping, occipital crest well developed ;3 or 4 (rarely 5) series of scales on cheek, 5 (rarely 6) from originof dorsal to lateral line ; D. XV-XVIII 9-10.8. novemfa&atus.B. Profile of snout steeply descending, occipital crest weak.3 to 6 series of scales on the cheek.1. 6 to 8 scales from origin of dorsal to lateral line; D. XVI-XVIII 8-10 ; A. I11 7-8.a. Width of tooth-band of lower jaw leas than) length of head ;. . 9. microstma.tooth-band slightly roundedb. Width of tooth-band of lower jaw ) length of head or(uaually) more ; tooth-band transverse.10. tropheops.Diameter of eye 3 to 39 in length of head, inter-orbital width 23 to 34 (in fishes of 80 to[tropheops.120 mrn.) ............................ 10 a. tropheopsDiameter of eye 3 to 3i in length of head, interorbitalwidth 3 to 38 (in fishes of 76 to112 mm.) ............................ 10 b. tropheops gracilior.2. 6 to 7 scales from origin of dorsal to lateral line ; D. XVII-XIX 8-10 ; A. I11 8-9 ; diameter of eye 24 to 34 in lengthof head, interorbital width 24 to 3f (in fishes of 76 to115 mm.) ...................... 11. macrophthalmus.1. Pseudotropheus eleqans, sp. n.A singlc specimen, 110 mm. in total length, from Deep Bay(coll. Christy).This species resembles P. livingstonii in the relatively narrowand rounded band of teeth and in the cmarginate caudal.The lnrgcr eye and somewhat narrower przcorbital distinguisllit from 11. livinqstonii ; also it has weaker jaws, the lowercontained three times in the length of head. The dentigerousarea of the lower pharyngeal is subtriangular instcad ofalmost heart-shaped, as it is in other species of Pseudotropheus.

74 Dr. Ethelwynn Trewavas on2. Pseudotropheus livingstonii (Boulenger), 1899. (Fig. 1.)Pseudotropheua willia*nsi (part.) Regan, Proc. Zool. Soc. Lond. 1921,p. 682.Seven specimens (coll. Christy), 95 to 150 mm. in totallength, from the southern end of the lake, re-establish thedistinctness of this species.The vertebrse, counted in one specimen, number 14f17.Fig. 1. Fig. 2.Fig. 1.-Pseudotropheus liwingstonii. Lower pharyngeal of a fish of105 mrn. x 5. a., anterior ; I., lateral ; p., middle posteriortooth, enlarged.Fig. 2.-Pseudotropheus zebra. Lower pharyngeal of a fish of 85 mm.x 63. Lettering as in fig. 1.3. Pseudotropheus zebra (Boulenger), 1899. (Fig. 2.)Pseudotropheua zebra Regan, t. c. p. 682.%.,&f'fJThe type (coll. Miss M. Woodm and fifteen specimens(coll. Christy), 63 to 104 mm. in total length, from both endsof L. Nyasa.The vertebrae, counted in two specimens, number 15f16.4. Pseudotropheus williamsi (Giinther), 1893.Pseudotr~hew, willicrmi (part.) Regan, t. c. p. 682.The type (coll. J. A. Williams) and twenty-five specimens(coll. Christy), 40 to 165 mm. in total length.The vertebra+ counted in one specimen, number 14+ 16.5. Pseudotropheus lucerna, sp. n.Ten specimens (coll. Christy), 90 to 135 mm. in total length,from Deep Bay.P. lucem has a larger eye and weaker lower jaw (oftenshorter than the upper anteriorly) than either P. zebra or

the Cichlid Fishes of Lake Nyasa. 7 5P. williamsi. Large specimens are easily distinguished fromP. zebra by the fact that the teeth remain bicuspid (outer)and tricuspid (inner), whereas in P. zebra they become simple.6. Pseudotropheus fuscus, sp. n.A single specimen, 82 mm. in total length (coll. Christy).This fish resembles P. williamsi in the dentition and in thesmall eye (3g in length of head), but differs from all otherspecies in the narrow interorbital region.7. Pseudotropheus auratus (Boulenger), 1897.Pseudotrophewr aurdwr Regan, t. c. p. 683.The type and forty-four specimens (coll. Christy), 40 to90 mm. in total length. Of these, 37 are females, 40 to 80 mm.long, and 7 are males, 70 to 90 mm.The extraordinary differences in coloration between thesexes, with the possibility that the males may be less numerousand larger, indicate that the breeding habits of this speciesmay be unusual. The ova are few and large, about ten ineach ovary ; thus efficient measures for the care of the broodmay be expected.8. Pseudotropheus novemfasciatus Itegan, 1921.Pseudotropheus novemfasciatwr Regan, t. c. p. 683.The type (coll. Wood), 66 mm. in total length, and fifteenspecimens (coll. Christy), 63 to 94 mm., from Deep Bay,Monkey Bay and the Bar, Lake Nyasa.The tooth-band, rounded in the young, becomes nearlytransverse in the adult.9. Pseudotropheus microstoma, sp. n.Two specimens (coll.Christy), 68 and 100mm. in total length,from Monkey Bay.These fishes resemble P. tropheops in every way except inthe very narrow mouth and curved tooth-band.10 a. Pseudotropheus tropheops tropheops Regan, 1921.Peeudorq?,hewr tropheops Regan, t. c. p. 683, text-fig. 3.The types (coll. Wood), 116 and 120 mm. in total length,and sixteen specimens (coll. Christy), 80 to 110 mm. long, aswell as a number of smaller specimens (coll.Christy), are typicdmembers of the species. They are all from the southern endof L. Nyasa. The vertebre, in one specimen, number 14+ 17.10 b. Pseudotropheus tropheops gracilior, subsp. n.Twenty specimens, 76 to 112 mm. in total length (coll.Christy), from Vua and Deep Bay, are, usually, more slender,

7 6 Dr. Ethelwynn Trewavas onand darker in colour than typical examples of P. tropheops,as well as having a larger eye and narrower interorbital region.11. Pseudotropheus macrophthalmus Ahl, 1927.Pseudotropheus mucrophthalmus Ahl, Sitzungsber. Ge s. naturf. Fr.Berlin, July 1926 (1927), p. 64.Fifteen specimens (coll. Christy), 76 to 115 mm. in totallength.These fishes resemble the typical specimens of P. tropheopsin the steep snout and low occipital crest, and are even moreextreme in both these characters. Thoy resemble P. tropheopsgracilior in the large eye. They differ from a11 P. tropheopsin the higher average number of dorsal fin-rays, especiallyspines. The colour appears to be uniformly pale ; even thefins are without spots or bands except the single bright spoton the anal in males. I have examined the type in Berlin.3. PETROTILAPIA, gen. nov.In the dentition this genus parallels Petrochromis of LakeTanganyika, but the relationships of Petrochromis are withthe Tilapia group, which it resembles in the fundamentalcharacter of the pharyngeal apophysis, of which the articularsurfaces are formed by the parasphenoid alone, whereas inPetrotilapia the basioccipital forms part of each facet. Thistype of dentition has, indeed, been evolved rnorc than oncein Tanganyika Cichlid*, as well as in Nyasa.A single species.Petrotilapin tridentiger, sp. n.Several specimens (coll. Christy), up to 155 mm. in totallength.In form, numerical characters, and coloration this speciesresembles PseudotropheiLs and Cyathochromis. Especiallynoticeable are the broad black submarginal band oftenpresent on the spinous dorsal, and one or two bright orangespots near the posterior edge of the anal.4. LABEOTROPHEU~ Ahl, 1927.Labeotropheus fuellebomi Ahl.Labeohvpheus ftielleborni Ahl, Sitzmgsber. Ges. naturf. Fr, Berlin,July 1926 (1927), p. 52.Labeotropheus curvirostris Ahl, t. c. p. 53.Numerous specimens (coll. Christy), 50 to 110 mm. in totallength, from Nkudzi and Deep Bay. The type has beenexamined by me in Berlin.There is a dermal thickening of the snout, immediatelyabove _the przemaxillary symphysis, producing the nose-like

the Ciclilid Fishes of Lake Nyasa. 7 7process characteristic of the types of L. fuelleborni. This isvcry weakly developed in the type of L. curvirostris, but,as the Christy collection contains intermediate specimens,I bclieve that there is only one species.The vertcbrac, counted in one specimen, number 14+16.5. CYATHOCHROMIS, gen. nov.Cyathochromis obliquidens, sp. n. (Fig. 3 .)Numcrous spocirnens, from Vua and the soutllern end ofthe lake, up to 150 mm. in total length (coll. Christy).This species is a Pseudotropheus in all except the dentition.The vertebrae, in two specimens, number 15+16.Fig. 3.Gyathochromw oblipuidens.a, anterior outer tooth of lower jaw ; b, two views of one of these ;c, two views of an inner tooth.6. CYNOTILAPIA Regan, 1921.Cynotilapia afra (Giinther), 1893.Cynotilapia afra Regan, t. C. p. 684.Known only from tho types, 85 and 95 mm. in totiil I~agth.'l'llc vcrtcbrm, counted in one specimen, number 15+16.7. CHRISTYELLA, gen. nov.Christyella nyasana, sp. n.13 or 14 gill-rakers on lower part of anterior arch. 32 scalesin :I, longitudinal series, 5 from origin of dorsal to 1atera.l line,7 or 8 between pectoral and pelvic fins. Dorsal XVIII 9.Anal 111 8. Colour pale brownish above, silvery below ;fins clear ; a bright spot near posterior edge of anal.A single specimen, 114 mm. in total length (coll. Christy).8. MELANOCIIROMIS, gen. nov.(type, M. melanopterus).This gonus is distinguishod from Pseudotropheus mainlyby the larger and fcwcr phsryngcd teeth, as may be seenby c8cml)ttrinq figure 4 \vith figures 1 and 2. For the dentitionof the jaws, sce fig. 5.

Fig. 4.Fig. 6.Fig. 4.-Lower pharyngeals of (A) Melanochromw brevis, (B) Melano.chromi8 melonopt-, and (C) Melanochromis ver~nivoru~.X 5.Fig. 6.-Melanochromia rnebnopterus. Dentition of jaws.

On the Cichlid Fishes of Lake Nyasa. 7 9Synopsis of the Species.I. Lips not lobed.A. Diambter of eye 4 to 6 in length of head ; 9 to 11 gill-rakers onlower part of anterior arch.1. Maxillary not reaching vertical from anterior edge of eye.Lower jaw 2t to 23 in length of head .... 1. melanopterms.Lower jaw 2) to nearly 3 in length of head ...... 2. vemivm.2. Maxillary reaching vertical from anterior edge of eye ; lowerjaw 2% to 3 in length of head ....... . 3. brevis.B. Diameter of eye 33 in length of head ; 12 gill-rakers on lowerpart of anterior arch ; maxillary reaching vertical from anterioredge of eye; lower jaw 2% in length of head. 4. prapkax.11. Lips produced into pointed lobes ; diameter of eye 33 in lengthof head ; 13 gill-rakers on lower part of anterior arch ; maxillarynot extending to below eye ; lower jaw 2) in length of head.6. lubrosus.The five species of Melrsnochrontis are all new to science,and all based on specimens in the Christy collection: M. melanopteruson 10 specimens, 76 to 118 mm. in total length, fromMonkey Bay ; M. vermivorus on 25 specimens, 65 to 95 mm.,from Nkudzi ; M. brevis on two specimens, 70 and 120 mm.long, from Nkudzi and Monkey Bay; M. perspicax on asingle specimen of 81 mm. from Deep Bay ; and M. lnbrosuson a single specimen of 54 mm. from Deep Bay.The vertebrae number 15+ 16 in a specimen of M. metanopterusand in one of M. vermivorus, 14+16 in the type ofM. perspicax,Fig. 6.,Genydrmnie mento. Dentition of jaws.9. GENYOCHROMIS, gen. nov.Qenyochromis mento, sp. n. (Fig. 6.)Depth of body 31 to 3& in the length. 6 to 8 series of scaleson the cheek. 8 or 9 gill-rakers on lower part of anterior

80 Dr. Ethelwynn Trewavas onarch. 32 or 33 scales in a longitudinal series, 7.from originof dorsal Go lateral line. Dorsal XVI-XVII 9-10. Anal111 7-8. Pectoral 3 length of head. Caudal truncate.Three specimens, one of 103 mm. (blackish, the soft verticalfins paler towards the margin) from Monkey Bay, and twoof 65 and 70 mm. (greyish, the spinous dorsal with a blackishsubmarginal band) from Nkudzi Bay (coll. Christy).10. LABIDOCHROMIS, gen. nov.Labidochromis vellicans, sp. n. (Fig. 7.)Depth of body 29 to 3& in the length. Snout with straightor slightly convex profile, from a little shorter than to 4diameter of eye, which is 3 to 4 in length of head. MouthFig. 7.Dentition of a 98 mrn. specimen ofLabidochromia vellicons.narrow, terminal ; maxillary ending a little behind nostril.4 to 6 series of scales on cheek. 8 to 10 gill-rakers on lowerpart of anterior arch. 30 to 32 scales in a longitudinal series,6 or 7 from origin of dorsal to lateral line. Dorsal XV-XVIII9-10. Anal I11 7-8. Pectoral 8 length of head. Caudaltruncate. Greyish or brownish, with or without 10 or 11dark cross-bars ; dorsal sometimes with a blackish submarginalband ; males with one or two bright spots nearposterior edge of anal.Several specimens (coll. Christy), 40 to 98 mm. in totallength, from Monkey Bay and Nkudzi Bay.The vertebre, counted in one specimen, number 15+15.

the. Cichlid Fishes of Lahe Nyasa.11. HAPLOCHROMI~ Hilgendorf, 1888.Ctenochromia Pfeffer, 1893.(Jyrtocara Boulenger, 1902.rlstatotilapk Pellegrin, 1904.C7hampsochrom.is Boulenger, 1916.Otopharynz Regan, 1920.Synopsis of the Nyasa Species of Haplochromis.I. Caudal rounded or rounded-subtruncate. 1. cdlipterw.11. Caudal truncate or emarginate.A. Body marked with large dark blotches, one or two of which arebehind, and at the level of base of pectoral ; blotches eitherexpanded vertically and interdigitating, or united by longitudinalbands, one at base of dorsal, one on upper lateral line,one along middle of side, and the fourth behind pectoral.1. Pectoral with small dark spots on the rays.a. 46 to 68 teeth in outer series of upper jaw.(i) Body not freckled. ........... 2. livingstonii.(ii) Body freckled.Lower jaw half length of head .............. 3. parddis.Lower jaw less than half length of head. ..... 4. polystigma.b. 80 teeth in outer series of upperjaw.. ........................ 6. muculimunus.2. Pectoral immaculate.Snout 1) to If diameter of eye ; lower jaw2) to 29 in length of head.. ............ 6. venuetua.Snout 1% to 2i diameter of eye; lower jawfrom lees than 2 to 2) in length of head..7. ficacottaniQtua.B. Six dark vertical bars on the body; occasionally also fainttraces of a longitudinal band above the lateral line and onealong middle of side ; middle pharyngeal teeth enlarged ;10 to 12 gill-rakers on lower part of anterior arch.8. johnstoni.C. Three longitudinal series of spots on the body, faintly united toform six cross-bars ; snout longer than postorbital part of head;pharyngeal teeth compressed, bicuspid ; 14 to 19 gill-rakers onlower part of anterior arch ........ 9. rostrdus.D. Colour-pattern, if present, consisting of a dark band or series ofspots along middle of side from caudal nearly to operculum,usually curved upwards near anterior end; often a secondband or series of spots above upper lateral line, and a third atbase of dorsal ; cross-bars, if present, numbering more thanfour below dorsal fin. Mouth not strongly protractile. Lipswithout median lobes, lower sometimes with a lobe oneach side of middle line.1. Snout longer than postorbital part of head.a. Depth of praeorbital 3) to 39 in length of head ; at dorsaloutline a stripe, continuous from snout to base of caudal.10. compressicepa.b. Depth of praeorbital 4 to 4% in length of head; at dorsaloutline a series of spots from nape to base of caudal.Ann. & Hag. N. Hist. Ser. 10. Vo1. xvi. 6

Dr. Ethelwynn Trewavas an(i) Interorbital width a to 5& in length of head.Depth of body 3 to 3) in the length ; pectoral8 to + length of head ................ 11. macrostoma.Depth of body less than 2% in the length (at215 mrn. total length) ; pectoral # lengthofhead .............................. 12. polyodon.(ii) Interorbital width 5) to 63 in length of head ; depth ofbody 3$ to 3# in the length ; pectoral not much morethan + length of head ...... 13. macdiceps.2. Snout not longer than postorbital part of head.a. Pharyngeal teeth all compressed, pointed, usually bicuspid,rarely a few slightly enlarged and even blunt.(i) Teeth in 2 or 3 series, outer conical, spaced, 30 to 45 inupper jaw in specimens of 100 to 200 mm. ; 10 to 13gill-rakers on lower part of anterior arch.Depth of praorbital 4& to 5 in length of head,length of lower jaw 2 to 2) ............ 14. urotznia.Depth of prreorbitalS2 to 6+ in length of head,length of lower jaw 24 to 23.. .......... 15. spiloptemcs.(ii) Teeth in 3 to. 6 series, outer bicuspid or tricuspid, or,if conical, more than 60 in upper jaw.a. Lower pharyngeal teeth small, but not minute, nordensely crowded posteriorly.* Outer teeth mostly tricuspid, 36 to 70 in upper jaw.16. trimodon.** Outer teeth bicuspid.8 31 to 33 scales in a longitudinal series ; 10 to 15gill-rakers on lower part of anterior arch.Lower jaw 3& to 34 in length of head ; 24 to 37teeth in outer series of upper jaw ...... 17. feneatratus.Lower jaw 2% to 3 in length of head ; 40 to 72teeth in outer series of upper jaw ;diameter of eye 3;) to 3) in length of head ;10 to 13 gill-rakers on lower part of anteriorarch .......................... 18. sirnilis.Mouth and teeth as in H. sirnilis ; diameterof eye 23 to 34 in length of head; 12 to15 gill-rakers on lower part of anteriorarch ................................ 19. marginatus.$8 33 to 36 scales in a longitudinal series.10 to 14 gill-rakers on lower part of anteriorarch ; depth of body 23 to 3 in the length,length of head 34 to 33.............. 20. leuciscus.18 gill-rakers on lower part of anterior arch ;depth of body 24 in the length, length ofhead 22 .............................. 21. spilonotus.*** Outer teeth conical in full-grown fish, bicuspid inyoung ; lower jaw 2& to 2) in length of head ;11 to 13 gill-rakers on lower part of anterior arch.Depth of prseorbital4+ to 5% in length of head ;D. XVII-XVIII 10-11 ; 32 to 34 scalesin a longitudinal series ................ 22. insignis.Depth of prmorbital32 to 4& in length of head ;D. XVI-XVII 11-12 ; 34 to 36 scales ina longitudinal scries .................. 23. annectens.

the Cichlid Fishes of Lake Nyasa.B. Lower pharyngeal toeth minute and numerous, denselycrowded, especially posteriorly.* Head 3 to 3) in length of fish; 11 to 13 gill-rakerson lower part of anterior arch.24. t~niolatus.** Head 3& to 33 in length of fish.8 13 to 15 gill-rakers on lower part of anterior arch.Depth of body 3 in the length; pectoral as longas head ; lower longitudinal stripe strong. 25. breviceps.Depth of body 29 to nearly 3 in the length;pectoral I+ to I$ as long as head; nostripes .............................. 26. microcephalus.$8 I4 to 17 gill-rakers on lower part of anterior arch ;depth of body 29 to 29 in the length ; depth ofprseorbital4 to 49 in length of head.27. nigritzniatw.$58 16 to 19 gill-rakers on lower part of anterior arch ;depth of body 24 to 3 in the length; depth ofprzorbital 46 to 6 in length of head.Interorbital width 3) to 3) in length of head ;46 to 64 teeth in outer series of upper jaw . 28. swenus.Interorbital width from nearly 4 to 44 in lengthgf head ; 66 to 72 teeth in outer series ofupper jaw. ........................... 29. purpumns.b. Lower pharyngeal with some or all of the middle teethenlarged and blunt.(i) Snout shorter than postorbital part of head.a. Head 3# to 3% in length of fish. 30. microstoma.8. Head from nearly 3 to 33 in length of fish.* Outer teeth bicuspid.Lower jaw 23 to nearly 3 in length of head . . 31. kirkii.Lower jaw 3 to 34 in length of head ........ 32. labridens.Lower jaw 3) in length of head ............ 33. virgatm.** Teeth conical ; lower jaw 2f in length of head.34. phenochilus.(ii) Snout as long as postorbital part of head ; head 28 inlength of fish (88 mm. specimen) ; outer teeth bicuspid,inner tricuspid ............ 35. festivw.E. A series of five spots at base of dorsal ; alternating with these,at least posteriorly, another series of spots on or above lateralline ; sometimes a third series ; spots often expanded vertically ;lips continuous, and produced at or near middle line.12 or 13 gill-rakers on lower part of anteriorarch ; posterior pharyngeal teeth withspherical crowns ...................... 36. omotw.16 gill-rakers on lower part of anterior arch ;posterior pharyngeal teeth large, but notspherical37. lobochilus.............................F. Two black longitudinal bands from head to caudal fin, one onmiddle of side, the other above upper lateral line and on upperedge of caudal peduncle; lips produced into median lobes ;tooth fow, outer compressed, 31) in uppor jaw; pharyngealteeth small ...................... 38. ruchil~m.6 *

Dr. Ethylwynn Trewavas onQ. A dark lateral band along middle of side, extending forwardethrough eye and across snout ; teeth conical, close-set, 60 to 94in outer series of upper jaw ........ 39. holotsnia.H. A dark stripe from operculum to caudal, not extending forwardsto eye ; teeth rather strong, cwed, conical, spaced.Lower jaw 2% to 23 in length of head ; 13 to 16gill-rakers on lower part of anterior arch . 40. kiwinge.Lower jaw 2 to 24 in length of head ; 11 to 13gill-rakers on lower part of anterior arch ;32 to 34 scales in longitudinal series .... 41. atrigatu8.Lower jaw 2Q to 2) in length of head ; 10 to 12gill-rakers on lower part of anterior arch ;34 to 36 scales in longitudinal series 42. dimidiatus.....J. A series of seven spots along back, the first in front of dorsal, thelast two on caudal peduncle ; a second series along upperlateral line, and a third below it ; spots of second and thirdseries usually fused to form an elongate blotch below spinousdorsal ; spots often united vertically to form cross-bars ;middle pharyngeal teeth enlarged and blunt.43. subocularis.K. An oblique band, or series of spots, from nape to base of caudal.1. Middle lower pharyngeal teeth enlarged, usually with roundedcrowns ; oblique band continuous or interrupted.a. Snout 13 to 21) diameter of eye (in specimens of 100 to195 mm. in total length) ...... 44. Eateristriga.b. Snout from a little shorter than to 14 diameter of eye (inspecimens of 65 to 200 mm.).(i) Head 2) to 3 in length of fish; caudal only slightlyemarginate.Lower pharyngeal with middle teeth moderatolyenlarged ...................... 45. incola.Lower pharyngeal with middle teeth greatlyenlarged, with spherical crowns ........ 46. rnola.(ii) Head 3 to 39 in length of fish; caudal moderately orrather deeply ernarginate ; pharyngeal teeth wellenlarged.A continuous dark band from nape to caudal,covering the posterior end of upper lateralline ................................. 47. aphsrodon.A series of spots from nape to caudal, one ofwhich is below posterior end of upperlateral line ; spots sometimes in partunited to form an incomplete band. ..... 48. ericotznia.(iii) Head 3 to 3% in length of fish; caudal only slightlyemarginate ; pharyngeal teeth little enlarged.Outer anterior teeth of jaws bicuspid, with themajor cusp rounded or truncate ........ 49. plagiotmia.Outer anterior teeth of jaws simple, compressed,with bluntly rounded or truncateends .............................. 50. labidodon.2. Pharyngeal teeth few, rather largo, but not with roundedcrowns ; black obliquo band continuous.a. Snout from a little shorter than to 14 diumetcr of eye.

the Cicldid Fishes of Lake Nyasa.52 to 56 outer teeth in upper jaw; obliqueband below posterior third of upperlateral line .......................... 61. balteatus.38 to 46 outer teeth in upper jaw; obliqueband on upper lateral line to its posteriorend, or nearly .................. 52. melanotsnia.b. Snout 18 to 12 diameter of eye; 30 to 38 outer teeth inupper jaw ; oblique band below posterior third of upperlateral line .................. 53. epichorialis.3. Lower pharyngeal teeth moderately small, compressed, bicuspid; black oblique band continuous, sometimes notdistinct from general dark colour of back.a. Teeth in jaws conical, curved, outer rather strong andspaced, 26 to 48 in upper jaw; chin strong; 36 to 38scales in a longitudinal series.Depth of body 3+ to 3% in the length ; XIV toXVII, usually XVI, dorsal spines ; adark bar on the praeorbital ............ 54. ~ilorhynchus.Depth of body 33 to 4% in the length ; XVI-XVIII dorsal spines, usually XVII ; preorbitalbar faint ...................... 55. csruleua.b. Outer teeth bicuspid or conical, 46 to 82 in outer series ofupper jaw in fishes of 120 mm. or more; mental ridgeweak or absent.(i) XVII-XIX, usually XVIII, dorsal spines; 34 to 36scales in a longitudinal series.a. No mental ridge; lower jaw flat, but strong, withbroad coronoid process; posterior teeth of upperjaw enlarged, often in 2 or more series.56. melanonotus.8. A slight mental ridge ; coronoid process slender ;teeth in a single series posteriorly.57. semiplatus.(ii) XVI or XVII dorsal spines ; 33 or 34 scales in a longitudinalseries; lower jaw weak, with slight mentalridge ; teeth very small and weak.Lower jaw inclnded, 23 to 3 in length of head . 58. guentheri.Jaws equal anteriorly, lower 29 in length ofhead.. .............................. 59. mollis.c. Teeth conical in adult, outer unequally bicuspid in young ;upper teeth buried in thick papillose lips, about 30 in outerseries ; mouth nearly vertical . . 60. orthognathus.d. Teeth conical in adult, outer bicuspid, inner unequally tricuspidin young ; outer forming a close-set series, of58 to 90 in upper jaw. Chin moderate to strong.(i) Lower jaw 2 to 2& in length of head in specimens of morethan 180 mm., 24 to 2# in specimens of 120 to 180 mm. ;snout 1& to 22 diameter of eye.U. 37 to 39 scales in a longitudinal series ; caudal pedunclela to twice as long as deep. . 61. lepturw.8. 36 to 37 scales in a longitudinal series ; caudal pedunclela- to 1% as long as deep.* Diameter of eye 33 to 49 (120 to 260 rnrn. specimens)or 5 to 6 (300 to 360 mm.) in length of head;maxillary extonding to below eye, or nearly.62. nototznio.

86 Dr. 1':tlielwynn 'I'rewavas on** Diameter of eye 4 to 52 (120 to 265 mm. specimens)or 6% to 63- (270 to 330 mm.) in length of head ;maxillary not extending to below eye.Back dark ; oblique band covering upperlateral line .......................... 63. rhoadesii.Back pale above oblique band, which is belowposterior half of upper lateral line ...... 64. heterotsenia.y. 33 to 36 scales in a longitudinal series.Diameter of eye 4 to 5 in length of head (145 to240 mm. specimens), depth of preeorbital32 to 43 ............................ 65. atritseniatus.Diameter of eye 3t to 4% in length of head (185to 260 mm. specimens), depth of prseorbital4 to 54...................... 66. oculatus.(ii) Lower jaw 2& to 23- in length of head in specimens of185 to 260 mm. ; snout 13 to 1% diameterof eye.Depth of body 3 to 34 in the length ; 35 to 37scales in a longitudinal series .......... 67. spectubilw.Depth of body 23 in the length ; 33 scales in alongitudinal series .................... 68. ohtusus.e. Outer teeth bicuspid, inner almost equally tricmpid ; lowerjaw 2Q in length of head ; snout less than 14 diameterof eye (specimens of 122 to 125 mm.).69. formosus.4. Lower pharyngeal teeth moderately small, compressed, bicuspid;a series of about ten dark spots obliquely fromnape to caudal.Diameter of eye 4) to 43 in length of head,depth of prseorbital6 to 6% ............ 70. gracilia.Diameter of eye 4 in length of head, depth ofpreorbital 6. ......................... 71. spiloatichua.L. A dark spot below, or sometimes touching, upper lateral line,another between the lateral lines, and a third at base of caudal;mouth not strongly protractile.1. Lower pharyngeal teeth all small and compressed.a. Maxillary extending to below anterior edge of eye, orbeyond ; 9 to 11 gill-rakers on lower part of anterior arch ;D. XV-XVII 9-12.Interorbital width 6 to 7 in length of head (infish of 115 to 160 rnrn.) ................ 72. ah&Interorbital width 54 in length of head (in a 5shof 62 mm.) .......................... 73. pkuroqilua.b. Maxillary not extending to below eye.(i) 14 to 18 gill-rakers on lower part of anterior arch;D. XVII-XVIII 10-12; diameter of eye 34 to 4in length of head, depth of przeorbital 3% to 4.74. auromaryinatua.(ii) 12 or 13 gill-rakers on lower part of anterior arch ;D. XVII-XVIII 10-11 ; diameter of eye 3) to 49in length of head, depth of przeorbital4) to 5% (in fisl~of 130 to 190 mm.) ........ 75. ovatus.liii) 9 to 12 gill-rakors on lower part of anterior arch ;D. XV-XVII 10-12.

the Cichlid Fishes of Lake Nyasa. 87a. Diameter of eye 3) to 44 in length of head, depth ofpraeorbital3a to 43 (in specimens of 115 to 210 rnm.).Pmmaxillary pedicel8 less than ) length ofhead ................................ 76. woodi.Praemaxillarypedicels &length of head or mom 77. modestus.p. Diameter of eye 44 in length of head, depth of praeorbital4) (in a fish of 106 mm.)78. pholidophorurr.2. Lower pharyngeal with a group of slightly enlarged teethposteriorly.Diameter of eye 34 to 4 in length of head (infish of 100 to 136 mm.) ; D. XV-XVI10-11 .............................. 79. tetrastigma.Diameter of eye 3 to 3) in length of head (infish of 86 to 128 mm.) D. XVII-XVIII9-11 ................................ 80. heterodon.M. Colour-pattern, if present, consisting of a dark spot or blotchon or above upper lateral line, often also another betweenthe lateral lines and sometimes overlapping one or both, anda third at base of caudal ; anterior spot often produced towardsnape, where there may be another large spot. Mouth notstrongly protractile.1. 10 to 13 gill-rakers on lower part of anterior arch.a. Lower pharyngeal with numerous minute teeth ; D. XVI-XVII 9-11 .................. 81. tetraspilus.b. Lower pharyngeal with moderately small, compressed teeth ;D. XVI-XVII 10-12.(i) Mouth wide ; 10 to 20 teeth in outer series of upper jaw.82. clwysogaster.(2) Mputh moderate ; 56 to 66 teeth in outer series of upperjaw.Maxillary ending half-way between nostril andeye ; diameter of eye less than ) length ofhead (in specimens of 163 to 200 mm. ormore) .............................. 83. labifer.Maxillary ending nearer to eye than to nostril ;diameterof eyeilength of head(in a specimenof 210 mm.) ...................... 84. speciosus.C. Lower pharyngeal with a group of enlarged teeth posteriorly.(i) 36 to 38 scales in a, longitudinal series ; D. XVI-XVII13-14 .................... 85. decorus.(2) 34 to 36 scales in 8 longitudinal series ; D. XV-XVII10-12.a. Depth of prreorbital 43 to 6%in length of head (in specimensof 74 to 145 mm.). ... 86. argyrosm.8. Depth of pmorbital 3% to 43in length of head (in specimensof 90 to 165 mm.).Anterior outer teeth bicuspid, 48 to 56 outerteeth in upper jaw ; no dermal hump on............................the headOuter teeth conical and directed outwards in87. aelenurua.adults ; 34 to 46 in uppor jaw ; a frontaldorn~al hump ........................ 88. momii.

8 8 Dr. Ethelwynn Trewavas on2. 7 to 9 gill-rakers on lower part of anterior arch ; lower pharyngealmassive, with large molarifom teeth.89. placodon.3. 16 to 39 gill-rakers on lower part of anterior arch ; lowerpharyngeal very slender, deeply notched behind, withslender, bicuspid teeth ; teeth in jaws small and weak.a. 16 to 18 gill-rakers on lower part of anterior arch.90. nitidus.b. 31 to 39 gill-rakers on lower part of anterior arch.Lower jaw 2 to 23 in length of head ........ 91. pictus.Lower jaw 2) to 2) in length of head...... 92. intermedius.N. Colour various ; upper jaw strongly protractile, the prremaxillarypedicels sliding well forwards when the lower jaw is depressed.1. 13 to 17 gill-rakers on lower part of anterior arch.a. Colour uniform, or with dark cross-bars; 16 to 17 gillrakerson lower part of anterior arch.Diameter of eye Q length of heed or more inspecimens of 86 to 95 mm., length of praemaxillarypedicels nearly 3 in length ofhead ................................ 93. inornatus.Diameter of eye less than Q length of head inspecimens of 88 mm. or more, length ofpraemaxillary pedicels 2) to 2) in lengthof head .............................. 94. eucinostomus.b. A dark band from operculum to caudal fin, traces of anotherabove upper lateral line, and a series of spots at base ofdorsal ; 13 to 16 gill-rakers on lower part of anterior arch ;diameter of eye less than ) length of head, praemaxiuarypedicels 2% to 3 in length of head . 95. postm.2. 17 to 23 gill-rakers on lower part of anterior arch.A dark spot on the side on and below upperlateral line, often another between thelateral lines, a third at base of caudal;praemaxillary pedicels 22 to 33 in length............................ 96. chrysonotus.of headNo spots,except one at base of caudal ; occasionallya stripe extending forwards from thisspot ; prremaxillary pedicels 2) to 2% inlength of head...................... 97. cyaneus.3. 20 to 28 gill-rakers on lower part of anterior arch ; colouruniform, or with a spot below upper lateral line, one onlower lateral line, and a third at base of caudal ; praemaxillarypedicels 2) to 2) in length of head. 98. quadrimaculatus.0. A single dark spot on each side of the body; upper jaw protractile; lower pharyngeal teeth small, numerous ; 18 gillrakerson lower part of anterior arch ; D. XIX 11.99. pleurostigma.P. Body-colour uniform, except for ten or eleven cross-bars whichmay be faint or well marked ; mouth not strongly protractile ;lower pharyngeal rather broad, with numerous minute teeth ;jaws weak, teeth minute.11 to 14 gill-rakers on lower part of anteriorarch ................................ 100. longimanus.16 or 17 gill-rakers on lower part of anteriorarch ................................ 101. micrentodon.

the Cichlid Fishes of Lake Nyasa. 89NOTES ON THE SPECIES OF HAPLOCHROMIS.1. Haplocromis callipterus (Giinther), 1893.Astatotilapia calliptera Pollegrin, 1904 ; Regan, Proc. ZooI. Soc. Lond.1921, p. 680.Haplochromw centropristoides Nichols & LaMonte, Amer.Mus.Novit. no. 451, 1931, p. 3, fig. 1.Numerous specimens, up to 140 mm. in total length, fromboth ends of the lake.2. Haplochromis livingstonii (Giinther), 1893.Haplochromis livingstonii Regan, Proc. 2001. Soc. Lond. 1921, p. 688.Eighteen specimens, 120 to 200 mm. in total length, fromthe south end of the lake.3. Haplochromis pardabis, sp. n.A single specimen, 190 mm. in total length, from DeepRay, near the north end of the lake.This shows the basic colour pattern of H. livingstoniiwith the spotting of H. polystigma, but has a larger eye andlarger mouth than either.4. Haplochromis polystigma Regan.Haplochromis polystigma Regan, t. c. p. 688, pl. i.Sixteen specimens, 105 to 230 mm. in total length, from thesouth end of the Iake.5. Haplochromis maculimanus Regan.Haplochromis rnaculimanus Regan, t. c. p. 689.Known only from the type, 190 mm. in total length.6. Haplochromis venustus Boulenger, 1908.Cyrtocara venusta Regan, t. c. p. 722.Haplochromis simulons Regan, t. c. p. 689, text-fig. 6.Fifty specimens, 110 to 225 mm. in total length, from bothnorth and south ends of the lake.As already noted, the presence or absence of lappets at thcedge of the membrane of the spinous dorsal fin is not of genericimportance, as was supposed by Boulenger and by Regan.The types of H. venustus are males. The gonads have beenremoved from the types of H. simulans, but the Iargestspecimen (190 mm.) is probably a female, to judge from thepaleness of the ground-colour and the distinctness of thepattern ; in it the lappets of the dorsal fin are well-developed.The lappets are well developed in males up to about 180 mm.,at which size a reduction begins to be obvious, and inspecimens of 185 mm. the edge of the fin-membrane is entire,or ncarly so, at lcast in the posterior lmlf of the spinous region.

90 Dr. Ethelwynn Trewavas on7. Haplochrmis fuscot~niatus Regan.Haplochromis fuscotzniatus Regan, t. c. p. 696, text-fig. 12.Six specimens, 143 to 220 mm. in total length, from thesouth end of the lake.8. Haplochromis johnstoni (Giinther), 1893.Haplochrmis johnstoni Regan, t. c. p. 691.Haplochrmis s~xfascicctua Regan, t. c. p. 692, text-fig. 7.Sixty-seven specimens, 60 to 170 mm. in total length,from both ends of the lake.The types of H. johnstoni and of H. sexfasciatus prove torepresent almost the extremes of a series showing differentdegrees of enlargement of the pharyngeal teeth.9. Haplochrornis rostratus (Boulenger), 1899.Haplochromis ro8tratus Regan, t. c. p. 718.Huplochromis mclcrorhynchus Regan, t. c. p. 717, text-fig. 28.Forty specimens, 105 to 255 mm. in total length, from bothends of the lake.The placing of H. macrorhynchus in the synonymy ofH. rostratus gives a species with a very wide rango of gillrakernumbers, but the differences in the shape of the snoutand the slope of the mouth show no constant correlation withhigh or low numbers.10. Haplochromis compressiceps (Boulenger), 1908.Haplochromis compreasiceps Regan, t. c. p. 717.Forty-six specimens, 100 to 210 mm. in total length, fromboth ends of the lake.11. Haplochromis macrostoma Regan.Haplochromis nwmostoma Regan, t. c. p. 719, pl. iv. fig. 2.Five specimens, 120 to 260 mm. in total length, from thesouth end of the lake.12. Haplochromis polyodon, sp. n.A single specimen, 215 mm. in total length, from Vua.13. Haplochrornis maculiceps Ahl.Haplochromis maculicep Ahl, Sitzungsber. Gea. naturf. Fr. Berlin,July 1926 (1927), p. 57.Two specimens, the type, 195 mm. (examined by mo inBerlin) and a specimen of 295 mm. in total length, both fromthe northern end of the lake.

the Cichlid Pishes of Lake Nyasa.14. Haplochromis urot~nia Regan.Raplochromis urotmia Regan, t. c. p. 696, text-@. 11.Thirty-three specitnens, 140 to 222 mm. in total length,from both ends of the lake.15. Haplochromis spilopterus, sp. n.Twenty-seven specimens, 100 to 200 mm. in total length,from both ends of the lake.Easily recognized by the broad mouth, with maxillary wellexposed, and the cleft at an angle of about 45" to thehorizontal. The narrow prajorbital and large eye (diameter3 to 4 in length of head) are also characteristic. In malesthe anal fin has two series of oval, yellow spots.16. Haplochromis trianodon, sp. n.Twenty-six specimens, 65 to 145 mm. in total length, fromthe south end of the lake.Very close to Ii. similis, from which it differs in the dentitionand in having 13 or 14 gill-rakers on the lower part of theanterior arch (10 to 13, usually 11 or 12, in H. similis).17. Haplochromis fenestratus, sp. n.Eleven specimens, 93 to 118 mm. in total length, eight ofwhich are from the north end of the lake, the rest from thesouth-west arm.This little fish, distinguished by its small mouth with fewteeth, usually has 9 to 12 dark vertical bars crossing thelongitudinal bands so as to produce a chequered pattern.28. Haplochromis similis Regan.Haplochromis sirnilis Regan, t. o. p. 693, text-fig. 8.Sixty-two specimens, 57 to 170 mm. in total length, fromboth ends of the lake.19. Haplochromis marginatus, sp. n.This species is near H. similis, but differs not only in thelarger eye and more numerous gill-rakers, but in havinga narrower prajorbitd and usually a larger mouth. There isa slight but constant difference also in the pharyngeal dentition,one or two teeth of each of the two middle series beingslightly enlarged in H. marginatus, but not in H. similis.Two subspecies are recognized, from the south and northends of the lake respectively.a. Haplochromis marginatus marginatus, subsp. n.Depth of body 24 to 22 in the length. Diameter of eye28 to 33 in length of head, interorbital width 3i to 3%, length

98 Dr. Ethelwynn Trewavas onof lower jaw 23 to 2%. 12 to 15 gill-rakers on lower part ofanterior arch. Dorsal XV-XVIII 10-11.Eighty-three specimens, 65 to 162 mm. in total length,from the south end of the lake (specimens of less than 105 mrn.not included in the description).b. Haplochromis marginatus vuaz, subsp. n.Depth of body 23 to 3 in the length. Diameter of eye 2$to 34 in length of head, interorbital width 39 to 34, lengthof lower jaw 24 to 2%. 12 to 14 gill-rakers on lower part ofanterior arch. Dorsal XVI-XVII 10-11.Fifteen specimens, 92 to 144 mm. in total length, fromVua, near the north end of the lake.Of seventy-six specimens of H. marginatus marginatus, onehas 12 gill-rakers on the lower part of the anterior arch, sevenhave 13, forty-six have 14, and twenty-two 15. Of the fifteenspecimens of H. m. vuaz, seven have 12, seven 13, and one 14.Of twenty-seven specimens of H. m. marginatus, seventeenhave a total of 26 dorsal rays, nine have 27, and one has 28.Of the fifteen specimens of H. m. vuaz, five have 26 dorsalrays and ten have 27.20. Haplochromis leuciscus Regan.Haplochronzis leuciscua Regan, t. c. p. 714, text-fig. 26.Forty-two specimens, 72 to 145 mm. in total length, fromboth ends of the lake.The colour is usually silvery, as in the types, but a faint,or rarely conspicuous, longitudinal dark band may be presentfrom operculum to base of caudal. This species is probablyrelated to H. breviceps and H. purpurans, but diffcrs fromthem in the pharyngeal dentition.21. Haplochromis spilonotus, sp. n.Two specimens, 130 and 165 mm. in total length, from DeepBay and the south-west arm of the lake.Most nearly related to H. marginatus.22. Haplochromis insignis, sp. n.Five specimens, 73 to 196 mm. in total length, from MonkeyBay. The proportions of the 73 mm. specimen are not includedin the synopsis.23. Haplochromis annectens (Regan) *, 1921.Cyrtouara annectena Regan, t. c. p. 723, text-fig. 30.Twenty-six specimens, 95 to 195 mm. in total length, fromboth ends of the lake.* This predates Haplochron~is annectens Regan (Proc. Zool. Soc.Lond. 1022, p. 168, text-fig. 2), a Luke Victoria fish, for which I heropropose the rmmo H. prodronms.

the Cicldid Pishes of Lake Nyasa. 93The edgesof dorsal and anal fins are entire in older specimens ;in younger fishes there are smell lappets between tbe spines.24. Haplochromis tzniolatus, sp. n.Seven specimens, 84 to 113 mm. in total length, from bothends of the lake.A series of cross-bars, sometimes more conspicuous thanthe longitudinal bands.25. Haplochromis breviceps Regan.Haplochromis breviceps Regan, t. c. p. 694, text-fig. 9.Fonr specimens, 130 to 150 mm. in total length, from thesouth end of the lake.26. Haplochromis microcephlus, sp. n.Two specimens, 122 and 125 mm. in total length, fromMonkey Bay.27. Haplochromis nigritzniatus, sp. n.Nine specimens, 135 to 204 mm. in total length, fromMonkey Bay.This species differs from the following in the pharyngealdentition (see below) and from H. purpurans in having fewerteeth in the outer series of the upper jaw (54 to 60), as wellas in the characters noted in the synopsis.28. Haplochromis serenus, sp. n. (Fig. 13 A, p. 114.)Thirteen specimens, 145 to 200 mm. in total length, fromVua and Deep Bay, near the north end of the lake.The lower pharyngeal bone of this species is broader andstoutcr than in either H. nigritzniatus or H. purpurans,less concave laterally, and with a pair of pronounced convexitiesposteriorly ; moreover, the pharyngeal teeth arca little larger.29. Haplochromis purpurans, sp. n.Fifteen specimens, 145 to 175 mm. in total length, fromthc northern end of the lake.30. Haplochromis microstoma Regan, 1921.Haplochromis microstoma Regan, t. c. p. 695, text-fig. 10.Twenty-one specimens, 80 to 190 mm. in total length,from both ends of the lake.31. Haplochromis kirkii (Giinther), 1893.Haplochromis kirkii Rogan, t. c. p. 693.15igll1,y-fivc spt.ci~nens, 86 to 180 mm. in total length, fronlbvt,ll oncls of the Iakc and from the Uppor ShirB liiver.

94 Dr. Ethelwynn Trewavas on32. Haplochromis tabridens, sp. n.Fifty-three specimens, 75 to 165 mm. in total length,from the south ond of the lake.These differ from Ii. kirkii in having a narrow praeorbitalbone (49 to 59 in length of head, as against 4 to 5 in H. kirkii),a shorter snout, and smaller mouth with, usuaIly, fewer teeth(26 to 40 in outer series of upper jaw as against 28 to 52 inH. i rk) Also the number of dorsal spines is usually XVin H. kirkii and XVI in H. labridens. In forty-two specimensof H. kirkii the spines number XIV in one, XV in thirty-seven,XVI in four. In the same number of H. labridens there isnone with XIV, there are XV in ten, XVI in thirty-one, andXVII in one.33. Haplochromis virgatus, sp. n.A single specimen, 125 mm. in total length, from MonkeyBay.The mouth is small and rather narrow, with thick lips.The anterior outer teeth are enlarged and bicuspid, the innersimple, in two series ; posteriorly there is a single scricsof small, simple teeth ; there are 26 teeth in the outer seriesof the upper jaw.34. Haplochromis phenochilus, sp. n.A single specimen, 157 mm. in total length, from Vua.The name refers to the lips, which are conspicuous by theirpallor.35. Haplochromis festivus, sp. n.A single specimen, 88 mm. in total length, from Nkudzi.This species may well be related to H. ornatus and 11. lobochilus,but is more generalized. The lobes of the lower lipare well developed, but are paired, one on each side of themiddle line. The gill-rakers number 13 on the lower part ofthe anterior arch.36. Haplochromis ornatus Regan.Hqloch.romis orncltua Regan, t. c. p. 691, text-fig. 6.Two specimens, 140 and 160 mm. in total length, one(type) probably from the south end of the lake, the otherfrom Karmga in the north.37. Haplochromis lobochilus, sp. n.A single specimen, 100 mm. in total length, from Deep Bay.38. Haplochromis eucl~ilus, sp. n.Two specimens, 05 and 115 mm. in total lcngth, fromDeep Bay.

the Cichlid Pishm of Lake Nyma. 95This species appears to be closely related to Chilotilapiarhoadesii; but differs in the structure of mouth and dentition.39. Haplochromis holotsnia.Paratilapia dimidiatn (part.) Boulenger, Cat. Afr. Fish. iii. p. 360,fig. 244 (1915).Haplochromis holotmia Regan, t. e. p. 697.Haplochromis bodyi Ahl, Sitzungsber. Gee. naturf. Fr. Berlin, July1926 (1927), p. 58.Twelve specimens, 170 to 200 mm. in total length, all(except perhaps the type) from the north end of the lake.The types of H. bodyi have also been examined by me.They mere taken at Langenburg.40. Haplochromis kiwinge Ahl.Haplochromis kiwinge Ahl, t. c. p. 56.Haplochromis fuelleborni (not Tilapia fuellebornii Hilgendorf & Pappenhoim),Ahl, t. o. p. 58.Fifty specimens, 125 to 290 mm. in total length, from bothends of the lake. Also thirty-three young of 50 to 117 mm.The types of H. kiwinge and H. fuelleborni have bee:]examined by me in Berlin.41. Haplochrornis strigatus Regan.Haplochromia strigatus Regan, t. c. p. 697, text-fig. 13.Sixty-four specimens, 108 to 223 mm. in total length, andtcn young, 48 to 100 rnm. long, from all parts of the lake.42. Haplochromis dimidiatus (Giinther), 1864.flaplochromis dintidiatus Regan, t. C. p. 698.Thirty specimens, 100 to 220 mm. in total length, and sixyoung fish (65 to 95 mm.), from both ends of the lake, butmainly from the north.43. Haplochromis subocularis (Giinther), 1893.Chromis subocularis Giinther, Proc. Zool. Soc. Lond. 1893, p. 621,pl. liv. fig. B.Haplochromis subocularis Regan, t. C. p. 600.Twenty-five specimens, 100 to 160 mm. in total length,from the south end of the lake.This species appears to be related to H. eriwtaznia, but isintermediate in colour-pattern between that species andH. kirkii etc. It differs from H. ericotaznia in having morescales in a longitudinal series (32 to 35, as against 30 to 33 inH. ericotznia) ; also the teeth in the jaws are usually in fewerscriea (3 to 5, as against 4 to 8 in H. ericotania), with 40 to 60in outer series of upper jaw (48 to 60 in H. ericotania) ; tho

96 Dr. Ethelwynn Trewavas oninner teeth are simple in the adult, unequally tricuspid inyoung, whereas in H. ericotaznia they are simple at all ages.44. Haplochrmis laferistriga (Giinthcr), 1864.Haplochromis lateviatriga Regan, t. c. p. 705, text-@. 18.Forty-four specimens, 100 to 195 mm. in total length,from both ends of the lake.45. Haplochromis incola, sp. n. (Fig. 8.)Eighteen specimens, 115 to 195 mm. in total length, fromboth e ~ds of the lake, mostly from the south.Fig. 8.Iiaplochromis incola. Lower pharyngeal of two spacimens.A, 120 mm. long (from Monkey Bay) ; B, 195 mm. (from Deep Bay.)46. liaplochromis naola, sp. n.Four specimens, 138 to 170 mm. in total length, from DeepBay and Vua ; also a young fish of 85 mm. from the southwestarm.The oblique band crosses the upper lateral line so as to lieon the ventral side of its posterior half.47. Haplochromis sphrerodon Rcgnn.Haplochromis spharodon Regan, t. c. p. 703, text-fig. 16.Six specimens, 80 to 115 mm. in total length.This species is distinguished from H. incola and Ii. molat)y the smaller head. The teeth in the jaws arc also morenumerous (44 to 60 in outer series of upper jaw in these

the Cichlid Fishes of Lake Ngasa.six fishes,not more than 50 in specimens of H. incola of 115 mm.,never more than 44 in H. mla). The pharyngeal teeth arelarger and more rounded than in H. inwla. It differs furtherf~om H. mola in having fewer and larger scales on the chest(5 between pectoral and pelvic fins in H. sphzrodon, 7 to I0in H. mola) and in the position of the oblique band, whichincludes the posterior end of the upper lateral line.48. Haplochromis ericotaznia Regan.Sixty-four specimens, 65 to 200 mm. in total length, fromboth ends of the lake.Very near H. splwrodon, but with smaller scales on thechest (7 between pectoral and pelvic fins), with a slightlysmaller eye and with the oblique band usually broken intospots. (See also notes on H. subocularis.)49. Haplochromis ptagwtz?nia Regan.Haplochromis plagiotrenia Regan, t. c. p. 706, text-fig. 19.Seventeen specimens, 70 to 110 mm. in total length.50. Haplochromis bbidodon, sp. n.Five specimens, 95 to 180 mm. in total length, from Mwayaand Deep Bay.The dentition of this fish is peculiar, the large anteriorteeth of the lower jaw grading rather sharply into the posterior.51. Haplochromis balteatus, sp. n.Three specimens, 106 to 162 rnm. in total length, fromKaronga and Vua. Three young fish, 68 to 90 mm., from thesouth-west arm, may also belong to this species.- 52. Haplochromis melanotaznia Regan.Haplochromis melanotznio Regan, t. c. p. 706, text-fig. 20.Four specimens, 120 to 180 mm. in total length, from thesouth end of the lake.This is easily distinguished from other fishes with an obliqueband by the thick lips and large mouth, and by the stout,subconical pharyngeal teeth.53. Haplochromis epichorialis, sp. ti.Two specimens, each 200 mm. in total length, from DeepBay.Lower pharyngeal rather large, bearing few large, ratherblunt, but not molariform teeth. 33 or 34 scales in alongitudinal series. Dorsal XVI 10-11. Anal 111 9. Spinesshort.Ann. & illag. N. Hist. Ser. 10. Vol. xvi. 7

98 Dr. Ethelwynn Trewrtvas on54. Haplochromis spilorhynchus Regan.Haplochromis qilozhynchw, Regan, t. e. p. 7 11, pl. vi. fig. 2.Haplochromis longipea Regan, t. c. p. 712, pl. v. fig. 2.Fifty-six specimens, 100 to 260 mm. in total length, fromthe south end of the lake.The type of H. longipes is a large male.55. Haplochrornis csruleus (Boulenger), 1908.Charnpaochmis cmlew Boulenger, Cat. Afr. Fish. iii. p. 433,fig. 295.Haplochromis czruleus Regan, t. c. p. 712.Haplochromis bellicosus Ahl, Sitzungsber. Ges. naturf. Fr. Berlin, July1926 (1927), p. 56.Haplochromis boultoni Nichols & LaMonte, Amer. Mus. Novit. no. 451,1931, p. 4.Eighteen specimens, 170 to 285 mm. in total length, fromboth ends of the lake.The type of H. betlicosus Ah1 has been examined by mein Berlin. It is larger than any of the British Museumspecimens, and has, as may be expected, a relatively widerinterorbital region.56. Haphchromis melanonotus Regan.Haplochronais melmumotus Regan, t. c. p. 708, text-fig. 21.Fifty specimens, 85 to 240 mm. in total length, from bothends of the lake.The peculiar jaws and dentition of this species would entitleit to generic rank were it not for its evident close relationshipto the following.57. Haptochromis semipalatus, sp. n.Three specimens, 173 to 185 mm. in total length, and a fishof 84 mm., from Kapora and Deep Bay.Teeth in 4 or 5 series, all conical, or anterior outer bicuspidor tricuspid and inner unequally tricuspid ; 54 to 64 in outerseries of upper jaw, the posterior enlarged.58. Haplochromis guentheri Regan.Eighteen specimens, 120 to 200 mm. in total length, fro~nboth ends of the lake.The weak jaws and weak teeth are unique in HnplociLromiu.The outer teeth of the included lower jaw project outwardsto meet those of the upper.59. Haplochromis mollis, sp. n.Two specimens, 106 and 160 mm. in total length, fromMonkey Bay.

the Cichlid Fishev of Lnlce Nyasa. 99The 106 mu. specimen has a relatively shorter lower jaw(nearly 3 in length of head), larger eye, etc. The jaws andteeth in this species are very similar to those of the genusLethriszops, but there is a short single series posteriorly inthe lower jaw.60. Haplochromis orthognathus, sp. n.Four specimens, 165 to 195 mm. in total length, from ratherdeep water in the south-west arm of the lake.Upper profile of hcad convex to between eyes, concavoin front. 33 scales in a longitudinal series. Dorsal XVI-XVII 9-10. Anal I11 8-9.61. Haplochromis lepturus Regan.Hapbchromis Iepturzls Regan, t. c. p. 709, text-fig. 22.Haploch.romis rhoadesii (part.) Regan, t. c. p. 710.Haplochrmnis gigas Ahl, Sitzungsber. Ges. naturf. Fr. Berlin, July1926 (1927), p. 65.Forty-five specimens, 115 to 400 mm. in total length.The type of H. gigas has also been examined by me in Berlin.Dr. Ahl's count of 35 scales in a longitudinal series wasobtained by counting in a straight line, including the lowerlateral line ; by the method used here the count is 38.Dorsal XVI-XVIII 11-13. Anal I11 9-11.62. Hapbchromis nototsnia (Boulenger).Haplochromw nototmia (part.) Regan, t. c. p. 709.Thirty-four specimens, 123 to 360 mm. in total length,from both ends of the lake.Dorsal XVI-XVIII 10-12. Anal TI1 9-11.63. Naplochromis rhoadesii (Boulenger).Haplochrontis rhoadesii (part.) Regan, t. c. p. 710.Twenty-four specimens, 120 to 330 mm. in total higth,from both ends of the lake.Dorsal XV-XVII 11-1 3.64. Haplochromis heterotsnia, sp. n.Two specimens, 145 and 210 mm. in total length.Dorsal XVII 11. Anal I11 10. These fishes have a somewhatlarger eye, shorter praemaxillary pedicels, and longerdorsal spines than specimens of H. rhoadesii of the same size,as well as differing in the coloration.65. Haplochromis atritsniatus Regan.Haplochromis atrilznialus Regan, t. c. p. 711, text-@. 23.Sixteen specimens, 165 to 240 mm. in total length, from thesouth end of the lake.Dorsal XV-XVl 10-13. Anal Ill 9-10.7"

100 Dr. Ethelwynn Trewavas on66. Haplochromis oculatus, sp. n.Haploehromia nototmia (part.) Regan, t. c. p. 709.Twenty specimens, 156 to 260 mm. in total length, fromthe south end of the lake.Dorsal XVI-XVII 11-12. Anal 111 9-10.67. Haplochromis spectabilia, sp. n.Eight specimens, 185 to 250 mm. in total length, from bothends of the lake.The seven preceding species are so closely related that itis worth while emphasizing the differences in the fin-counts,as shown by frequencies and averages in the followingtable :-Total number of rays.r26. 27. 28. 29. 30. Average.H. lepturus .......... 3 36 6 29-07H. nototsniu ...... 6 21 6 1 28.09H. rhoadeaii.. ...... 6 19 2 .. 27.85H. heterotzniu.. ...... 3 .... 28.00H. atritzsniatzcs . . 4 12 . . . . . . 26-75H. oculatus ........ 13 7 .... 27.35H. spectab& ...... 1 4 3 .. 28-2668. Haplochromis obtusus, sp. n.A single specimen, 220 mm. in total length, from the southend of the lake.Dorsal XVIII 9. Anal I11 10. Diameter of eye nearly69 in length: of head, depth of prsorbital 49, interorbitalwidth 3#, lower jaw 24.69. Haplochromis formosus, sp. n.Two specimens, 122 and 125 mm. in t,otal length, from Vua.Very near to the following, but with a smaller eye and deepcrpraeorbital than would be expected in young of H. gracilis.In H. fornaosus also the oblique dark band is continuous, andthere is a dark bar on the prseorbital.70. Haplochromis gracilis, sp. n.Three specimens, 200 to 210 mm. in total length.Dorsal XVII 12-13. Anal I11 10. 36 or 37 scales ina longitudinal series. 11 or 12 gill-rakers on lower part ofanterior arch.71. Haplochromis spilostichus, sp. n.A single specimen, 220 mm. in total length, from MonkeyBay.

the Cichlid Fishes of Lake Nyasa. 101Dorsal XVIII 12, Anal I11 10. 38 scales in a longitudinalseries. 13 gill-rakers on lower part of anterior arch.72. Haplochrmis ahli, nom. nov.Haplochromis serranoides (non Regan) Ahl. Sitzungsber. Ges. naturf.Fr. Berlin, July 1926 (1927), p. 64.Nineteen specimens, 115 to 160 mm. in total length, fromboth ends of the lake.The type has been examined by me in Berlin. It is largerthan any of the British Museum specimens, and has, accordingly,a wider interorbital region (nearly length of head).73. Haplochromis pleurospilus, sp. n.A single specimen, 53 mm. in total length, from Lupembesand-bank, in the northern part of the lake.32 scales in a longitudinal series. Dorsal XV 12. Anal 11110.This small fish is probably not closely related to H. ahli.74. Haplochronais auromarginatus (Boulenger), 1908.TGapia auromarginata Boulenger, Cat. Afr. Fish. iii. p. 180, fig. 116(1915).Otopharynx aunmzarginatus Regan, t. c. p. 678.Fifteen specimens, 145 to 240 mm. in total length, fromboth ends of the lake.In the males no spots are visible on the body, and the generalcoloration is much darker thm in females.75. Haplochromis ovatus, sp. n.Three specimens, 130 to 190 mm. in total length, from thesouth end of the lake.76. Haplochromis woo& Regan.Haplochromis woo& Regan, t. c. p. 702, pl. ii.Eighty-one specimens, 115 to 230 mm. in total length,from all parts of the lake.Fifty-eight of these, from the south end of the lake, agreewell with the types. In a very uniform sample of nine specimenstaken together between Fort Johnston and Nkudzithe body is more slender, the eye is rather large (34 to nearly4 in length of head), and the scale-counts differ slightly fromthose of the fifty-eight (33 to 35 in a longitudinal series asagainst 32 to 34 ; 4, rarely 5, between origin of dorsal andlateral line, as against 5 or 6, rarely 4 ; 6 to 8, rarely 5,between pcctoral and pelvic fins, as against 5 or 6, rarely 7).Twenty-throe specimens from the north end of the lake,including all the largest specimens, have a larger eye (diameter

102 Dr. Ethelwynn Trewavas onalways more than ) length of head), narrower interorbitalregion (6 to 74 in length of head, as against 5 to 6Q), andsomewhat longer prsmaxillary pedicels. The fin-ray countsof the dorsal fin resemble those of the sample of nine ratherthan those of the more typical specimens.Nine specimensand Nkudzi.Total ofdorsal rays.Typical H. woodifrom the south.Northernspecimens.from betweenFt. Johnston25 1 0 026 40 3 227 16 10 728 1 1 077. Haplochromis modestus (Gtint,lier).Haplochromis modestus Regan, t. c. p. 701.Known only from the type, 150 mm. in total length.Very near H. woodi, from which it is distinguished by thelarger mouth and by the prsmaxillary pedicels, which extendnearly to between the orbits. Also in specimens of H. woodiof this size the eye is usually larger and the interorbitalwidth less.78. Haplochromis pholidophorus, sp. n.A single specimen, 105 mm. in total length, from Vua.Snout longer than postorbital part of head. Teeth conical,in 3 series in upper jaw, 2 in lower, 50 in outer series of upperjaw. 11 gill-rakers on lower part of anterior arch. 32 scalesin a longitudinal series. Dorsal XVI 12. Anal I11 10.79. Haplochromis tetrastigma (Giinther). (Fig. 9.)Haplochromis tetmtigma Regan, t. e. p. 699.Seventy-four specimens, 44 to 136 mm. in total length,from both ends of the lake.The dentition of the lower jaw in many specimens of thisspecies is like that of Lethrinops, although in others thereis a short single series posteriorly. It is possible that thisspecies is in a transitional stage between the two genera.80. Haplochromis heterodon, sp. n.Eleven specimens, 86 to 128 mm. in total length, fromDeep Bay and Monkey Bay.Teeth in 3 or 4 series, inner tricuspid, outer bicuspid, orsome tricuspid, or, in larger specimens, simple. 11 to 14gill-rakers on lower part of anterior arch. 32 or 33 scalesin a longitudinal series. Caudal peduncle as long as deep ora little longer.

the Cichlid Fishes of Lake Nyasa. 103A fish from Monkey Bay has 9 gill-rakers on the lowerpart of the anterior arch on one side, 10 on the other, butotherwise cannot be separated from this species.Pig. 9.Haplochromis tetrmtigma. Dentition of lower jaw.81. Haplochromis tetraspilus, sp. n.Ninety-six specimens, up to 156 mm. in total length, fromthe south end of the lake.Mouth small ; maxillary ending below nostril or a littlebehind. Teeth in 3 or 4 series, outer bicuspid, inner tricuspid.30 to 32 scales in a longitudinal series. Dorsal XVI-XVII9-11. Anal 111 9-10.82. Haplochromis chrysogaster, sp. n.Three specimens, 150 to 175 mm. in total length, fromKaronga and the south-west arm of the lake.

104 Dr. Ethelwynn Trewavas onLower jaw rather strong, with prominent chin. Teethin 2 series in upper jaw, 3 in lower, rather small, embeddedin papills of the gums, outer with one, two, or three cusps.34 scales in a longitudinal series. Dorsal XVI 10. AnalI11 9-10.83. Haplochromis tabyer, sp. n.Six specimens, 163 to 217 mm. in total length, from bothends of the lake.Snout 14 to 1$ diametor of eye. Lowcr jaw rathcr prominent.Tceth in 3 or 4 serics above, 3 below, si~uple, or outer bicuspidand inner tricuspid ; 56 to 62 in outer series of upper jaw.32 to 34 scales in a longitudinal series. Anal 111 8-10.Caudal peduncle 1) to 14 as long as deep. Colour-patternin larger males masked by general dark coloration.84. Haplochromis speciosus, sp. n.Two specimens, from Vua and Monkey Bay, 210 and 245 mm.in total length.Snout 14 to 18 diameter of eye. Teeth in 3 series, outersimple, inner simple or unequally tricuspid, 66 in outerseries of upper jaw. 33 or 34 scales in a longitudinal series.Anal I11 9. Caudal peduncle 19 as long as deep.85. Hapbchromis decorus, sp. n.Six specimens, 108 to 165 mm. in total length, from bothends of the lake. ,There is a tendency for the dark blotches to become elongatedand to unite to form a more or less broken oblique band.86. Haplockromis cargyrosoma Regan.Haplochromis argyrosoma Regan, t. c. p. 713, text-fig. 28.Eleven specimens, 74 to 145 mm. in total length, from bothends of the lake.The spots, or blotches, of the colour-pattern are sometimeslacking, as in the type. Teeth in 3 series, outer bicuspid,inner tricuspid or simple ; 44 to 60 in outer series of upperjaw. Caudal crescentically emarginate. Caudal peduncle16 to 12 as long as deep.87. Haplockromis selenurus ((Rcgan).Otopharynx selenurus Regan, t. c. p. 679, text-fig. 1.Nineteen specimens, from both ends of the lake, 110 to165 mm. in total length.The uolour is often uniformly purplish brown, darker above,especially on nape ; a vague dark blotch above upper lateral

the Cichlid Fishes of Lake Nyasa. 105line in some is all that is visible of the colour-pattern, exceptoccasionally traces of about eleven cross-bars.88. Haplochromis moorii (Boulenger) , 1902.Cyrtocara moo& Boulenger, Cat. Afr. Fish. iii. p. 445, fig. 304 (1915);Regan, t. c. p. 724.Forty-nine specimens, 67 to 195 mm. in total length, fromboth ends of the lake.This very distinct species appears to be related toW. srlenurus, from which it differs chiefly in the dentition,in the prosence of a dermal frontal hump, and in tho lessemarginate caudal fin. The dermal hump is present inboth sexes and increases with age at a rate showing considerableindividual variation.89. Hnplochromis plncodon Regan.Haplochromis placodon Regan, t. c. p. 700, text-fig. 15.Sixty-eight specimens, 105 to 195 mm. in total length,from both ends of the lake.This well-marked species seems to be more closely relatedto Trenaatocranus than to any species of Haplochromis, butshows no sign of enlargement of mucus-canals.90. Haplochromis nitidus, sp. n.Eleven specimens, 80 to 139 mm. in total length, fromboth cnds of the lake.Tecth in 2 series, occasionally with an incomplete third,minute, outer conical in adult, bicuspid or tricuspid in young,40 to 76 in outer series of upper jaw. 31 or 32 scales in alongitudinal series. Dorsal XV-XVI 11-13. Anal I11 8-10.The dark patches on the side are very conspicuous, andmay be elongated antero-posteriorly so as almost to meet.91. Haplochromis pictus, sp. n.Eight specimens, 103 to 126 mm. in total length, fromboth ends of the lake.Teeth as in H. nitidus ; 60 to 84 in outer series of upperjaw. 31 to 33 scales in a longitudinal series. Dorsal XV-XVII 10-12. Anal I11 9-10. Colour-pattern very conspicuous.92. Haplochrmis intermdius (Giinther), 1864. (Fig. 10.)Haploclwromis intermedius Regan, t. c. p. 701.Twenty-three specimens, 45 to 212 mm. in total length,from the south end of thc lakc. One of these is the type,a skin, in which gill-rakers and pharyngeal bones were not

106 Dr. Ethelwynn Trewavas onpreserved. The dentition and proportions are, however,unmistakable.93. Haplochromis ino~natus (Boulenger), 1908.Tdtzpia inornola Boulenger, Cat. Afr. Fish. iii. p. 263, fig. 178 (1916).Haplochmis inwnatus Regan, t. c. p. 716.Known only from the types, two specimens, 85 and 95 rum.in total length.Fig. 10.Haplocl~romis intermedius.A, Lower jaw ; B, lower pharyngeal ; C, first gill-arch.94. Haplochromis eucinostomus Regan.Haplochromis ezccinostmua Regan, t. c. p. 761, pl. iv. fig. 1.Twenty-two specimens, 88 to 125 mm. in total length,probably from both ends of the lake.Teeth very small, in 2 or 3 series, outer simple or bicuspid,inner simple or tricuspid, 40 to 50 in outer series of upperjaw. 34 or 35 scales in a longitudinal series. Dorsal XV-XVII 11-12. Anal I11 9-11. Caudal crescentically emarginate.Caudal peduncle I+ to 13 as long as deep.95. Haplocliromis prostma, sp. n.Six spocimem, 76 to 115 mm. in total length, from Vua andDeep Ray.Tceth as in El. eucinostomus. 33 or 34 scalos in a longitudinalseries. Dorsal XVI-XVII 11-12. Anal I11 9-10. Caudalemarginate. Caudal peduncle 1i to 12 as long as deep.

the Cichlid Fishes of Lake Nyasa.Externally this species closely resembles specimens of'H. cyaneus that have the same colour-pattern, but specimensof Ii. cyaneus that have as few as 17 or 18 gill-rakers arerare, and only one of H. prostoma has as many as 16, andeven this not on both sides. Moreover, in H. cyaneus thopr~maxillary pedicels are a little shorter.96. Nnplochromis chysonotus (Boulenger), 1908.Paratilapin chrponota Boulenger, Cat. Afr. Fish. iii. p. 362, fig. 246(1915).Haplochro,nis chry.sonotus Regan, t. c. p. 702.One hundred and twenty-one specimens, 76 to 163 mm.in t,otal length, from both ends of the lake.Teeth in 3 or 4 series, conical ; 50 to 70 in outer seriesof upper jaw. 31 to 34 scales in a longitudinal series. DorsalXV-XVII 9-12. Anal I11 9-11. Caudal emarginate. Caudalpeduncle as long as or a little longer than deep.Males often have a bright yellow dorsal fin and back.97. Haplochromis cyaneus, sp. n.Sixty-two specimens, 100 to 190 mm. in total length.from 110th ends of the lake.Teeth in 2 or 3 series, all simple, or some outer bicuspldand inner tricuspid ; 50 to 64 in outer series of upper jaw.31 to 34 scales in a longitudinal series. Dorsal XVI-XVIII10-12. Anal 111 9-11.98. Hapbochromis quadrimaculatus Regan.Haplochromis quadrimaculatus Regan, t. c. p. 703.Sixky-sevon specimens, 108 to 200 mm. in total length,from both ends of the lake. Also eighteen young fishes,38 to 92 mm. long.Teeth in 2 to 4 series, very small, conical, 50 to 74 in outerseries of upper jaw. 32 to 36 scales in a longitudinal series.Dorsal XVI-XVIII 10-12. Anal I11 10-12. Caudal emarginate.Caudal peduncle from as long as to 1+ times as longas deep.This species is very variable in form. The Christy collectionincludes some very slender specimens, with long caudalpeduncle and rather deeply emarginate caudal fin, tbat contrastsharply with the deep-bodied form represented by someof the types and by other specimens of all sizes ; but theextremes are linked by intermediates.99. Haplochromis pleurostigma, sp. n.A singlo spcci~non; 195 mm. in total lcnglh, from Deep Bay.This fish bea,rs some rcsemblancc to fi. serenus, but hasa larger head, longer lower jaw, deeper caudal peduncle, and

108 ,Dr. Ethelwynn Trewavas onless emarginate caudaI fin, as we11 as a different coloration.The teeth are conical, in 4 series, with 68 in the outer seriesof the upper jaw. There are 34 scales in a longitudinal series.100. Haplochromis longimanus, sp. n.Forty specimens, 85 to 145 mm. in total length, from thesouth end of the lake.Closely related to H. rnicrentodon, from which it differsin the number of gill-rakers. Also the eye is usually a littlesmaller in specimens of a given size.101. Rnplochromis micrentodon Regnn.Haplochromia micrentodon Regan, t. c. p. 716, text-fig. 27.Three specimens, 110 to 150 mm. in total length, from thesouth end of the lake.12. COREMATODUS Boulenger, 1896.Coremtodus Boulenger, Cat. Afr. Fish. iii. 1916, p. 494, fig. 342.1. Corematodus shiranus Boulenger.Cormotodua uhiranua Boulenger, Proc. Zool. Soc. London, 1896,p. 919, fig. 4.Diameter of eye 38 to 5 in length of head, equal to or greaterthan preorbital depth ; interorbital width 24 to 4 in lengthof head. Teeth in about 10 (young) to 20 series in broadestpart of upper jaw. 31 to 34 scales in a longitudinal series.Dorsal XV-XVI 10-12. Anal I11 9-10. Caudal truncate.5 to 10 narrow blackish cross-bars on body, the first fromorigin of dorsal to opercular spot; one or two transversebands on nape and one or two curved bands from eye to eye.Thirteen specimens, 86 to 230 mm. in total length, fromthe south end of the lake and the Upper Shire River.2. Coremtodus taniatus, sp. n.Diameter of eye 3 to 34 in length of head, much greaterthan prajorbital depth ; interorbital width 3& to nearly 5in length of head. Teeth in about 7 (young) to 10 series inbroadest part of upper jaw. 31 to 33 scales in a longitudinalseries. Dorsal XV-XVII 9-10. Anal I11 8-10. Caudaltruncate or slightly emarginate. An oblique dark band fromnape to base of caudal ; a series of spots at base of dorsal.About thirty specimens, 82 to 170 mm. in total length,artd a few smaller (coll. Christy).13, Doc~~onus Boulenger, 1896.A single species, D. johnsfoni Boulcngcr (1896, and Cat.Afr. Fish. iii. p. 282, fig. 192 (1915) ; Regan, t. c. p. 722).

the Cichlid Fishes of Lake Nyasa. 10914. LETHRIN~PS Regan, 1921.To the synopsis of this genus already given (Trewavas,1931) the following species has now to be added :-Lethrinops intermedia, sp. n. (Fig. 11.)Snout from a little shorter to a little longer than diameterof eye, which is 3$ to 3% in length of head. Lower pharyngealFig. 11.Lethrinops intermedia. Lower pharyngeal from aboveand from the side.o., anterior ; p., posterior tooth of 8 middle series.with short, descending, anterior blade ; anterior pharyngealteeth bicuspid, with ends directed forwards, middle posteriorenlarged and blunt. Dopth of praorbital 4 to 4+ in lcngthof head. 8 to 10 gill-rakers on lower part of anterior arch.of body 2% to 2g in the length. Dorsal XV 10-11.Anal 111 8-9. Colour silvery or dark purplish ; sometimestraces of eight vcrticd bars below dorsal fin ; a dark patch

110 Dr. l

the Cichlid Fishes of Lake Nyasa. 111Fig. 12.C'l~iLotil(~pia r7wadc8ii.Der~tition of jimws ill (A) young ( x 0) and (B) adult ( x 3).

112 Dr. Ethylwynn Trowavas on17. RHAMPHOCHROMI~ Regan, 1921.Synopsis of the 8pecies.I. 36 to 40 scales in a longitudinal series ; caudal peduncle 1)to 2 as long as deep.A. Teeth moderate, 20 to 30 on each side of upper jaw.1. longiceps.B. Teeth fewer and stronger.1. Eyes rather large, diameter 5 to 6) in length of head (inspecimens of 200 to 400 nim.)...................... 2. macrophtlmlmus.in length .................... 3. hrevis.2. Eyes smaller, diameter 53 to 8) in length of head (in spocirnensof 190 to 420 mm.).Depth 4 to 44 in length.Depth 3f to 3%Snout ) length of head or a little less, interorbitalwidth 43 to 5 in head, premaxillariesfrom symphysis to end of pedicels 33 to 3%. 4. woodi.Snout 3 head or a little less ; interorbital width39 to 4) in head, prremaxillaries 4 to 44.. .. 5. few.Snout a little more than f head, 1) times postorbitallength ........................ 6. lucius.11. 40 to 45 scales in a longitudinal series ; caudal peduncle 2 to 29as long as deep.Profile of snout convex: interorbital width 3)to 4 in length of head, length of lower jaw2)to 23 .............................. 7. eaot.Profile of snout straight ; interorbital width 4 to44 in head, lower jaw 2 to 24 ............ 8. leptosoma.1. Rharnphochromis longiceps (Giinthcr), 1864.Rhamphochrmis longieeps Regan, t. c. p. 724.Eleven specimens, 190 to 250 mm. in total length, fromboth ends of the lake.2. Rhamphochromis macrophthalmus Regan.Rhamphochrmi llulc~ophthalmus Regan, t. o. p. 725, pl. vi. fig. 2.Eight specimens, 200 to 270 mm. in total length, fromboth ends of the lake.3. Rharnphochromis brevis, sp. n.Five specimens, 255 to 400 mm. in total length.4. Rhamphochromis woo& Regan.Rhampho&rm& woo& Regan, t. o. p. 725.Ten specimens, 160 to 420 mm. in total length, from bothends of the lake.5. Rhamphochromis ferox Regan.Rhamphochromis ferox Regan, t. c. p. 725.Fourteen specimens, 100 to 430 mm. in total length, fromboth ends of the lako.

the Cichlid Fiehes of Lake Nyasa. 1136. Rhamphochromis lucius Ahl.Rhamphochrontis lucius Ahl, Sitzungsber. Ges. naturf. Fr. Berlin, July1926 (1927), p. 69.Two specimens, each 360 mm. in total length, from DeepBay and Monkey Bay. I have examined the types in Berlin.7. Rhnmphochronzis esox (Boulenger), 1908.Rharnphochromis esox Regan, t. c. p. 726.Eight spscinm~s, 175 to 370 mm. in total length, fromboth ends of tho Inkc.8. Rhamphochromis leptosoma Regan.Rhantphochromis leptosomca Regan, t. c. p. 726.Rhamphochromis melanotus AM, t. c. p. 60.Eight specirncns, 330 to 380 mm. in total length, from bothends of the lake.The types of H, melanotus have been examined by me inBorlin. I count only 5 or 6 series of scales on the cheek. Thescales, counted by our method, number 42 to 44 in a longitudinalseries. My sketch of the head of the smaller specimen(310 mm.) shows it to be a typical R. leptosoma. The largerspecimen, of which I have no drawing, may perhaps belong toR. esox.18. TREM ITOCRANUS, gcn. nov.(type, T. microstoma).Otic region of skull slightly swollen ; mucus-cavities ofsuborbital bones not greatly swollon ; cheek with 2 to 4series of scales. In Nyasa this genus stands in the sarnc!relation to Aulonocara that Aulonocranus does to Trematocarain Tanganyika.Spopsis of the h'p~cies.A. Inner teeth of jaws unicuspid or (young) tricuspid, with middlecusp much bigger than lateral.Snont short ; upper jaw 38 to 34 in length of head ;pl~i~ryngc~ul tooth not rriuch onlargod .......... 1. brevirosfris.Snout long ; uppor jaw 3% to 4 in length of head ;pharyngenl tenth considorably cnlarged ........ 2. microstma.B. Inner teeth of jaws with three subequal cusps.. 3. auditor.1. l'rematocranus brevirostris, sp. n. (Fig. 14, B.)Snout shorter than diameter of eye, which is 245 to 3 inlength of head. 9 to 11 gill-rakers on lower part of ant~riorarch. 32 or 33 scales in a longitudinal series. Dorsal X\'10-11. Anal 111 9. Poctoral as long as head. Ca11&11podun~le a littlc longor than deep. Body with about elevclllverticnl bars ; n spot' on upper lateral line below spinous

114 Dr. Ethelwynn Trewavas ondorsal, one below soft dorsal and a third at base of caudal ;an opercular spot.Two young specimens (coll. Christy), 53 and 72 mm. intotal length, from the bar at the south end of Lake Nyasa.2. Trematocranus microstoma, sp. n. (Pig. 13, B.)Snout, in large specimens, longer than postorbital part ofhead ; diameter of eye 4 to 5 in length of head. 10 or11 gill-rakers on lower part of anterior arch. Teeth slender,curved, pointed, in 6 to 8 series anteriorly. 32 to 34 scalesin a longitudinal series. Dorsal XV-XVI 11-12. And I119-11. Pectoral as long as head or longer. Caudal peduncleas long as or a little longer than deep. A dark blotch on nape,another on upper lateral line below spinous dorsal, a thirdbelow soft dorsal, and a fourth, often faint or absent, atbase of caudal ; an opercular spot.Fig. 13.Head-skeleton of (A) Haplochromis serenu, (B) Trematocranwmicrostoma. Both natural size.Twenty specimens (coll. Christy), 140 to 232 mm. in totallength, one from the sout'h end of Lake Nyasa, the rest fromthe northern part of the lake.This species bears a resemblance to Haplochromis placodonin coloration, in dentition of jaws and pharyngeals, in numberof gill-rakers, etc. It is also, and more nearly, related toAulonocara rostrata. Probably Ii. placodon is the Haplocromismost nearly representing the stock from which Trematocranusand Aulonocara have ,evolved.3. Trematocranus auditor, sp. n. (Fig. 14, A.)Snout a little shorter than diameter of eye, which is 3kin length of head. Teeth in four series, those of lower jawforming a rather broad band anteriorly, giving place abruptlyto a single series posteriorly on each side. 11 or 12 gill-rakerson lower part of anterior arch. 33 scales in a longitudinalseries. Dorsal XVI 10. And I11 0. I'ect,ord not quite

the Cichlid Fishes of Lake Nyascz. 115as long as head. Caudal peduncle la as long as deep. Elevendark vertical bars on each side, bearing a series of spots atbase of dorsal, anot,her series on upper lateral line, arid a, thirdserios below and parallel to the second.Three specimens, one (coll. Christy) 96 mm., the others(coll. Rhoades) 77 and 84 nlm. in total length. The Christyspecimen is from Vua.That this species may not be closely related to the othertwo is suggested by the different dentition, smaller head, anddifferent coloration.Fig. 14.Dentition of lower jaw in (A) Tremcctocranw, auditor,(B) Trematocranus brevirostrk, x 10. Single teeth, x 20.29. AULONOGARA Began, 1921.Aulonocara Regan, Proc. Zool. Soc. 1921, p. 726.In this genus the otic region is more bullate than in Trematocranus,and the suborbital bones are so much enlarged as tooccupy the whole cheek to the exclusion either of all thescales or of all but a single complete series. The enlargementofthe other mucus-channels of the head has proceededfarther than in Trematocranus.Synopsis of the Species.1. Diameter of eyo more than 4f in length of head in specimens of150 mm. or more.Length of snout 29 to 34 in length of head, interorbitalwidth4to49 ................................ 1. nyassg.Length of snout 24 to 2$ in length of head, interorbitalwidth 4% to 59. ............................... 2. rostrata.2. niumctcr of oyo 4f UI length of head in a specimen of 170 mm.3. macrochir.

116 Dr. Ethelwynn Trewavas on1. Aulonocara nyassa Regan.Aulonoma nyassa Regan, Proc. Zool. Soc. Lond. 1921, p. 727, pl. v.fig. 1.In addition to the three types (coll. Wood), the BritishMuseum (Nat. Hist.) collection now contains forty-threespecimens (coll. Christy), 50 to 180 mm. in total length.The original description must be modified to include thelarger specimens. Teeth in 4 to 8 series, outer bicuspidin young, all slender and conical in larger specimens. Noscales on cheek in young ; a single series and occasionallyone or two of a second series in large specimens. A few middlopharyngeal teeth slightly enlarged.2. Aulonocara rostrata, sp. n.Distinguished from A. nyassse by the longer snout andnarrower interorbital region. Also, even in older specimens,scales are absent from the cheek, or there is only a single,incomplete series. The young of both species have thebody marked with a number of vertical bars, but in A. nyassz9 or 10 of these are below the dorsal fin, in A. rostrata 6 or 7.Twenty-seven specimens (coll. Christy), 48 to 180 mm. intotal length.3. Aulonocara mcrochir, sp. n.Distinguished by the larger eyo and by the long pectoralfin, longer than the head. In the other species the pectoraldoes not exceed the head in lengt'h.A single specimen, 170 mm. in total length (coll. Christy).20. DIPLOTAXODON, gen. nov.Near Haplochrornis. Mouth oblique ; toet,h conical, biserinl.Paired laminar inferior apophyses extending the whole lengthof third or third and fourth vertebrae.Diplotaxodon argcnteus, sp. n.Depth of body 34 in the length, length of head 23 to 3.Head 24 to 3 as long as broad. Snout with straight profile.,longer than diameter of eye, which is 34 to 34 in length ofhead, greater than depth of prsorbital or cheek ; interorbitalwidth 5 to 6 in length of head. Mouth very oblique ; lowerjaw strongly projecting ; maxillary not nearly reaching eye ;teeth conical, in two well-separated series, the outer larger,rather strong anteriorly, 60 to 70 in upper jaw. 3 series ofscales on cheek. 23 to 25 gill-mkcrs on loww part of anteriorarch. Pharyngeal teeth small, bicuspid ; 14 or 15 in a middloseries. 34 to 36 scales in a longitudinal series, 5 from origi~lof dorsal to lateral line. Dorsal XR-SV 11-13 ; spinr~

the Cichlid Fishes of Lake Nyasa. 117slendcr, last 3 length of hcad. Anal I11 10-11 ; third spinestronger and shorter than last dorsal. Pectoral 4j to % lengthof head, not reaching anal. Caudal emarginate. Caudalpeduncie 19 to 1% as long as deep. Silvery.Three specimens, 170 to 180 mm. in total length, from thesouth end of the lake ; also a skeleton.21. LICHNOCHROMIS, gen. nov.Near Haplochrornis, but without inferior apophyses onanterior vertebra Snout long ; mouth narrow ; praemaxillariesproduced and beak-like. Teeth in a single seriesexcept anteriorly ; outer teeth compressed, entire, notchedor distinctly bicuspid.Lichnochromis acuticeps, sp. n.Dopth of body 33 in the length, length of head 24. Snoutstraight, oblique, nearly length of head; pr~niaxillarypedicels % length of head ; lower jaw projecting ; maxillaryending below nostril ; teeth of outer series close-set ; in front2 or 3 inner series of smaller teeth, the anterior pair of thefirst lower series somewhat enlarged. 4 series of scaleson cheek. 12 gill-rakers on lower part of anterior arch.Pharyngeal teeth small. 33 scales in a longitudinal series,5 from origin of dorsal to lateral line. Dorsal XVI 11 ;last spine 4 length of head. Anal I11 9 ; third spine strongerand a, little shorter than last dorsal. Pectoral # length ofhead, reaching origin of anal. Caudal scdy, emarginate.Caudal peduncle 19 as long as deep. A dark bar from eyeto maxillary ; two curved bars across snout, and anotheracross anterior part of interorbital region ; a transverseband across posterior part of interorbital region, an opercularspot ; a blackish oblique band from nape to base of caudal ;dorsal spotted.One specimen, 125 mm, in total length.22. ARISTOCHROMIS, gen. novI+~haps related to H~xplochromis rbrrdesii. The stronglycxnpressed head reoalls that of the Labrid Xyrichthya.A~istochromis christyi, sp. n.Dopth of body 3 in the length, length of head 23 to 3.Upper profile of head convex to in front of eyes, then declivous.Snout as long as or a little shorter than postorbital part ofhead ; diameter of eye 5 to 69 in length of head, less thanprmx%ital depth, 8 to 8 dopth of cheek ; interorbital width6 to 8 in length of head. Przmaxillaries beak-like anteriorly,projerting a little beyond lower jaw ; f dtL of upper lip n:Lrrow,

118 On the Cichlid Fishes of Lake Nyasa.widely interrupted ; maxillary extending to below eye ;teeth small, conical, in 3 or 4 series anteriorly. 5 to 7 seriesof scales on cheek. 10 to 12 gill-rakers on lower part ofanterior arch. Pharyngeal teeth small. 34 to 36 scalesin a longitudinal series, 5 or 6 from origin of dorsal to lateralline. Dorsal XV-XVII 11-13 ; last spine from less than4 to + length of head. Anal I11 9-11 ; third spine strongerand as long as or shorter than last dorsal. . Pectoral # to Qlength of head. Caudal densely scaled, truncate or somewhatemarginate. Caudal peduncle 15 to 18 as long as deep. Headusually with irregular spots, body sometimes with cross-bars ;a blackish band or series of spots at base of dorsal, extendingon to upper edge of caudal peduncle ; an oblique blackishband, mainly below upper lateral, and from nape to middleof base of caudal ; 'soft dorsal usually spotted.Nineteen specimens, 130 to 250 mm. in total length.23. SERRANOOHROMIS Regan, 1920.One species in Lake Nyasa.Serralzoclironzis tliumbergi (Castelnau), 1861.Serrodmie thumb& Regan, t. o. p. 264.Katanga and Angola to Lake Nyasa.Numerous specimens; up to about 380 mm. in total length,from both ends of the lake.

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