J 2 Mr. C. T. Uccrnn—aassijlcatwn of 



11. ASPKOTILAPIA, Bouleng., 1001 

 (typo -1. leptiu-a, Boulen<r.). 



"Dorsnl XIV 14. Anal III 8. Scales denticulate, larfje 

 (38) ; two lateral lines. Snout conical ; mouth inferior, 

 transverse; teeth in jaws slender, tricuspid, in narrow trans- 

 verse bands. Lower pharyngeal subtrian<^ular, with slender 

 teeth. Skeleton essentially similar to that of Ophthalmo- 

 iilapia ventralis^ except that the nasal bones are broad 

 posteriorly. Vertebras 35 (lG + 19). 



Tanganyika; a single species. 



This genus differs from Ophthalmot'dapla in the strictlv 

 transverse and inferior mouth, with the bands of teeth not 

 extending backwards at the sides. 



12. PetkOCIIROMis, Bouleng., 1808 

 (type P. polyodon, Bouleng.). 



Dorsal XVII-XX 8-10. Anal III 7-8. Scales finely 

 denticulate, large (32-35). Mouth subterminal ; lips very 

 thick, the upper with a double fold; teeth very slender, tri- 

 cuspid, in very broad bands. Lower pharyngeal subtriangular, 

 witii moderately long anterior blade. Occipital crest extend- 

 ing forward in advance of parietal crests, which end above 

 middle of orbits near edges of frontals ; ethmoid united with 

 vomer by suture ; nasal bones not expanded posteriorly ; 

 paras))henoid with a pair of facets for articulation of upper 

 j>h;\ryngeals. Vertebrre 32 (16 4- 16) ; inferior apophj-ses of 

 third short, separate. 



Two species from L. Tanganyika and one from L. Nyassa. 



This genus is essentially similar to Ophthahnotilapia in 

 skeletal structure. 



13. CYATHOniAUYNX, gen. nov. 

 (type Tilapia granducidis, Bouleng.). 



Dorsal XIII-XIV 12-14. Anal III 9-10. Scales den- 

 ticulate, small (55-65); two lateral lines, the upper nearly 

 reaching caudal fin. Moutli small,. subterminal ; maxillary 

 concealed; jaws with 3 to 5 series of slender pointed teeth, 

 wither Avithout small lateral cusps; teeth of the outermost 

 series enlarged, in the lower jaw directed outwards. Lower 

 j)haryngeal with nearly circular, slightly concave dentigorous 

 area and rather long anterior blade ; teeth numerous, close- 

 set, slender. Occipital crest extending forwards to middle 

 of interorbital region, ending behind a median groove on 



