168 Field Columbian Museum — Zoology, Vol. V. 



dorsal s ightly nearer tip of snout than page 



base of caudal patzcuaro 174 



hh. Anal rays 13 or 14; gill rakers 4+17=21; 

 scales 54-12; body dark, opaque, scarcely 

 compressed; depth 6%; origin of spinous 

 dorsal nearer tip of snout than base of 

 caudal by a distance greater than diam- 

 eter of eye zirahuen 174 



gg. Origin of spinous dorsal midway between 

 base of caudal fin and anterior margin of 

 orbit, or nostril; anal rays 17 to 19; scales 

 1 5-54 ; gill rakers 4+15 = 19 ; species of large 



size humboldtianum 175 



ff. Scales with crenate edges; origin of spinous 

 dorsal nearer base of caudal than tip of the 

 snout; anal rays 18 to 24. 

 i. Snout short, 3^ in length of the head, being 

 equal to or shorter than the diameter of 

 the eye; species of small size, 

 j. Scales in lateral series 49, transverse 13; 

 anal base equals the length of the head, its 



rays 21 chapalce 176 



jj. Scales in the lateral series 62, transverse 14; 

 base of anal fin 1% in the length of the 



head, its rays 19 grandocule 176 



ii. Snout long, 2% to 2^ in the length of the 

 head; diameter of eye 4^ to 5^ in head; spe- 

 cies of large size. 



I. Upper jaw decidedly longer than the lower, 

 mandible 2]/ 2 in the head; tip of snout 

 black; base of anal fin i>^ in the head, its 

 rays 19 or 20; scales 15-53 to 56; teeth 

 large, not in definite rows; snout 2% in 



head; diameter of eye 5^; gill rakers 5 + 19 promo' as 177 



II. Lower jaw decidedly longer than the upper; 

 mandible i-i to 2 J in the head; tip of jaws 

 not black (dusky in some specimens). 



m. Scales between dorsal fins very small, 

 more than 20 in a series between the 

 fins ; scales 2 2-60 to 70 ; gi 1 rakers ?+ 23 ; 

 teeth large anteriorly, canine-like, not 

 arranged in definite rows ; mandible 2 in 

 head sphyrcBua 177 



