1914.1 



NATURAL SCIENCES OF PHILADELPHIA. 



231 



branched dorsal ray trifle longer than head; first branched anal 

 ray If hi head; pectoral 1|; ventral 1^. 



Body elongate, robust, moderately compressed, and deepest at 

 dorsal origin. Predorsal with slight or obsolete keel just before 

 dorsal origin, other edges of body all convex, and that of preventral 

 broad and flattened, or only very obsolete keel or ridge along outer 

 boundaries. Lower profile evenly convex. Caudal peduncle com- 

 pressed, small, about long as deep. 



Head robust, somewhat pyramidal, upper surface slightly de- 

 pressed, and lower broadly convex, convex sides not especially 

 converging below. Upper profile slightly convex, less inclined than 



J'ifi 



-Chilodus labyrinthicus rupununi Fowler. (Type.) 



lower. Snout broadly triangular as seen from above, surface convex, 

 and length about half its width. Eye large, circular, high, and a 

 little anterior in head. Adipose-eyelid broad, exposes most of very 

 broad pupil. Mouth small, terminally inferior, and seen below 

 transversely crescentic. Upper jaw with single series of small weak 

 filament-like teeth, none in lower jaw. Maxillary small, upper edge 

 slips below preorbital, and slightly expanded distal end reaches 

 opposite posterior nostril. Mandible small, shallow, each ramus 

 well elevated inside mouth. Tongue well back, large, depressed, 

 free. Nostrils well developed, superiorly lateral, together, in last 

 third of snout length, anterior with well-developed cutaneous rim 



