FAMILY XIV. ATHERINID^E. 167 



c. Base of anal much longer than head, its ray PAGE 



19 to 21 ; scales 40; origin of spinous dorsal 



nearer tip of snout than base of caudal fin mezquital 170 



cc. Base of anal equal to or shorter than head, 

 d. Origin of spinous dorsal over tips of ven- 

 trals, midway between base of caudal and 

 nostril. 



e. Body robust, its depth 4^ in the length 

 of the body; base of anal i-J- in the head, 

 its rays 16 or 17; scales 11-38 to 40; teeth 

 large, sharp, in two definite rows in each 

 jaw; gill rakers long and slender, 3 + 11 to 



14 on first arch arge 171 



ee. Body slender, its depth 6 in the length of 

 the body; scales 10-42; anal rays 15; gill 

 rakers long and slender, 4+17 on the first 



arch bartoni 172 



dd. Origin of spinous dorsal over middle of ven- 

 trals, being nearer tip of snout than base of 

 caudal by a distance equal to the diameter 

 of the eye; base of anal if in the head, its 

 rays 13 or 14; gill rakers 4 + 18=22; teeth 



very small attenuatum 172 



ddd. Origin of spinous dorsal over space between 

 tips of ventrals and origin of anal fin, mid- 

 way between base of caudal and posterior 

 margin of orbit ; base of anal fin equaling 

 length of the head, its rays 20; teeth large, 

 in a single row, except near tip of upper 

 jaw; few anterior teeth large, canine-like 



scales 12-42 ; gill rakers 4+13 labarca 173 



aa. Scales smaller, more than 45 in the lateral 

 series; edges of the scales usually crenate; 

 vertebrae more than 40. 



f. Scales entire ; base of anal about if in length 

 of head, its rays 13 to 19; snout 3 to 3^ in 

 length of head, 

 g. Origin of spinous dorsal nearer tip of snout 



than base of caudal fin. 



h. Anal rays 17; gill rakers 4+21 =25; scales 

 12-48; body light, translucent, sl'ghtly 

 compressed; depth 5^; origin of spinous 



