48 CALIFORNIA ACADEMY OF SCIENCES. 



as the head; pectoral spine as long as head without 

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

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

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

 ther.) coerulescens 49. 



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

 rine patches. 



H. Dorsal I, 6-7. F"ontanel 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; adipose fin 

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

 as long. Otherwise like (juatemalensis.\ (Giinther) 



assimilis 51. 



DD. Granulations of the head continued forward to between 

 the eyes. 



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

 bital area without 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 process 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 3j?; depth 6. D. 

 1,7. A. 18. t (Bleeker.) surinamensis 52. 



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

 cess; interorbital area with 4 granular ridges. 

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

 anal ray less than 2 in head. dasycephalus 53. 



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

 est anal ray 2 in head. lonyicephalus 54. 

 CC. Teeth on the palate in two patches. 



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



continued as a groove. 



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

 angular behind; intermaxillary band of teeth four times as 

 wide as deep; palatine patches of teeth less than diameter 

 of eye in width. rugispinis 55. 



*Based on specimens .30 m. long. 

 tBased on a specimen .33 m. long. 

 {Based on a specimen .268 in. long. 



