of the Ge}iu.<! VaWoimh ^c. 203 



2. 3Jicrothn'ssa royauxi. 



Microthrhsa roynnxi, Boulencr. Ann. Mns. Congo, ii. 1902, p. 26, and 

 Cat. Air. Fish. i. p. 161, tig.''l29 (1909). 



Depth of body 3-3| in the lengthy length of licad A. 

 Snout shot ter than diameter of eye, which is 3 in length of 

 liead ; jaws equal ahteiiorlj; maxillary with minute teeth, 

 extending to below anterior margin of eye ; 14 gill-rakers on 

 lower ])art of anterior arch. 38 to 40 scales in a lonuitudinal 

 series, 12 in a transverse series ; ventral .«cutes 12-13+ 6-7. 

 Dorsal 13 ; origin equidistant from end of snout and 

 base of caudal, heiiind the 8-rayed pelvics. Anal 23 (-25), 

 extending forward nearly to below end of dorsal. Caudal 

 ])edunch' a little deeper than long. 39 vertebrse. 



Ill.anghi R. 



One of the types, 55 mm. in tot.d length, from Banzyville. 



4. PoTAMOTHRlSSA, gen. uov. 



Closely related to Pi Uonula, but maxillary narrow, supia- 

 niaxilLiry bone quite small, and no teeth on tongue or on 

 maxillary. Dorsal fin of 13 or 14 rays, placed well forward, 

 its origin much nearer to end of snout than to bfise of caudal, 

 above or in advance of first ray of pi Ivies ; anal of 17 or 18 

 ray.«, far b. hind dorsal. Scales 40-44/10. Vertebrae 42. 



1. Potamotkrissa ob/usiro.'itriii. (Fig. 1,2.) 



Pellonula obtusirostns, Bouleno. Cat. Afr. Fish. i. p. lo8. tiff. 126 

 (1909). I' ^ o 



Jaws equal anteriorly. IG gill-rakers on lower part of 

 anterior arch. Ventral scutes 9-10+9-10. 

 Aruwimi River, Congo. 

 Two specimens, 72 mm. in total length. 



2. Potamothiissa acutirostris. 

 Pellonula acutirostris, Bouleiig. Cat. Afr. Fish. i. p. 159, fig. 127 (1909), 



Lower jaw shorter than upper. 19 gill-rakers on lower 

 part of anterior arch. Ventral scutes 12-13+- 10-12. 

 Upper Congo, 

 Five specimens, up to 75 mm. in total length. 



5. Cynothrissa, gen. no v. 



Differs from Pellonula in the very prominent lower jaw 



and in the presence of an inner series of pnemaxillaiy teeth, 



