THE CYPRINODONTS. 45 



Cnesterodon scalpridens sp. n. 



Plate V. Fig. 12, teeth; Plate VIII. Fig. 17, male. 



B. 5; D. 7; A. 9; V. 6; P. 11; LI. 28-29; Ltr. 7 ; Vert. 14+15. 



Elongate, moderately compressed, depth and length of head about equal, 

 one fourth of the length, without the caudal. Snout short, blunt, rounded, 

 not as long as the eye. Mouth narrow, oblique, directed upward ; lower jaws 

 longer, rather firmly joined ; upper short, protractile. Teeth chisel-shaped, 

 broad and close together in the outer series ; inner series scattered in a 

 band, small, tricuspid. There are eight incisors on each mandible. Eye 

 large, longer than the snout, about three times in the head, or one and one 

 half times in the forehead. Dorsal origin opposite that of anal, midway from 

 occiput to base of caudal. Ventrals small, reaching the anal. Pectorals 

 elongate, reaching the bases of the ventrals. Caudal large, longer than the 

 head, subtruncate or slightly convex. Anal of male modified, longer than 

 the head, much advanced. In this sex the second rays of the ventrals also 

 are elongate. Scales large, intestine long. 



Light olivaceous, edges of scales darker, lower half of cheek and belly 

 silvery to golden. A faint streak of silvery, on a single row of scales, be- 

 tween the opercle and middle of the base of the caudal, frequently contain- 

 ing a black line. Top of head dark ; top of snout light. Fins uniform, or 

 dorsal puncticulate toward the base. The largest females measure one and 

 one eighth inches ; the largest males three fourths of an inch. 



Amazon basin : Santarem ; Obidos ; Tapajos ; Villa Bella ; Trombetas. 



GIRARDINUS. 



Oirardinus Poey, 1855, Mem., I, 383, 390,-1861, Mem., IT, 383 (part), — 1868, Repert., II, 411 

 (part) ; Blk., 1860, Cypr., 481, 484 (part), — 1863, Atl., Ill, 139 ; Gth., 1866, Cat., VI, 351 (part). 



Outlines similar to those of Gambusia. Body compressed, caudal pedicel 

 deep, body cavity nearly half of the total length. Head depressed, broad 

 and flattened on the crown. Snout broad, short ; chin short, steep. Mouth 

 wide, directed upward ; jaws short, weak, loosely joined, lower longer, upper 

 shorter, protractile. Teeth slender, movable, hooked, contracted at the 

 base, broadened, spatulate or shovel-shaped, toward the apex, in a single 

 series on each jaw without or with a few very small pointed teeth in bands 

 behind them. Branchiostegal rays five. Dorsal fin behind the middle of 



