48 CALIlFORNIA ACADEMY OF SCIENCES. 



as the head; pectoral spine as long as head without 

 snout. Sides steel-bhie, iridescent; blackish above, sil- 

 very below; vertical fins black; inner side of paired fins 

 blackish. Head 3i-3f; depth 5; D.I, 7; A. 17.* (Gitn- 

 ther.) cosrulescens 49. 



GG. Palatine patches of teeth much larger than the vome- 

 rine patches. 



H. Dorsal I, 6-7. Fontanel almost obsolete, ending be- 

 tween the eyes; head two-thirds as wide as long. 



guatemalensis 50. 



HH. Dorsal I, 7. Fontanel ending midway between 



tip of snout and middle of dorsal plate; adii^ose fin 



shorter than the dorsal fin; head three-fourths as wide 



as long. Otherwise lilie i/uaiemalensis.'l (Giinther) 



asaimilin 51. 

 DD. Granulations of the head continued forward to between 

 the eyes. 



/. Fontanel not continued backward as a groove; interor- 

 bital area w^ithout ridges; adipose fin about as high as long, 

 shorter than the dorsal fin. Depth of head 1| in its length; 

 width 1^. Eye 5^ in the head, 2\ in the interocular, less 

 than 2 in snout. Occipital jirocess not longer than broad, 

 not conspicuously keeled. Snout depressed; upper jaw 

 little longer. Vomer and palatine teeth contiguous. Max. 

 illary barbels reaching to the base of the pectoralsl 

 Opercle smooth. Dorsal spine shorter than the pectora- 

 spine, about 2 in the head, granulated in front, striated on 

 sides. Caudal 4 in the length. Head 3?; depth 6. D. 

 I, 7. A. 18. t (Bleeker.) surinamejisis 52. 



//. Fontanel continued as a groove to base of occipital pro- 

 cess; interorbital area with 4 granular ridges. 

 J. Head 4J in the length; dorsal spine 1| in head; highest 

 anal ray less than 2 in head. dasycephahis 53. 



J J. Head 3| in the length; dorsal spine If in head; high- 

 est anal ray 2J in head. longicephalus 54. 

 CC. Teeth on the palate in two patches. 



K. Eye small, about 10 in the length of the head; fontanel not 

 continued as a groove. 

 L. Sides of the dorsal and pectoral spines granular; fontanel 

 angular behind; intermaxillary band of teeth four tirades as 

 wide as deep; palatine patches of teeth less than diameter 

 of eye in width. rurjisinnis 55. 



*Based on specimens .30 m. long, 

 t Based on a specimen .33 m. long. 

 JBased on a specimen .268 m. long. 



