224 CALIFORNIA ACADEMY OF SCIENCES. 



mi. Caudal emargiiiate; humeral process wide, sword-shaped; 



snout entirely covered with skin; adipose fin longer than the 



dorsal fin. marmoratus 175. 



ddd. Dorsal spine smooth on both margins. (AMBLYDOBAS.) 



q. Caudal rounded; head not keeled, fontanel small, oval; eyes 

 longer than the snout, 1 in the interorbital. Prenasal bone 

 finely dentate. Maxillary barbels reaching to the tip of the 

 humeral process. Lateral plates almost entirely covered with 

 skin, with a median hook and marginal spines. Pectoral spine 

 longer than the dorsal spine, reaching beyond base of ventrals; 

 caudal rounded. Back brown, lower surface light, everywhere 

 spotted with darker. Caudal barred. D.I, 6; A. 12; P. I, 5; 

 V. 7; Lat. 1. 25-26. affinis 176. 



qq. Caudal emarginate; lateral scutes low; a light band extends 



obliquely upward from base of pectoral to the lateral scutes, 



thence backward to the caudal fin; three large, elongate, dark 



blotches above and below the lateral band. iveddellii 177. 



bb. Pectoral spine consisting of a spine only;* caudal rounded. 



(CENTROCHIB.) CTOCOdill 178. 



aa. Prenasal bone raised, crest-like, deeply pectinate. 



r. Dorsal spine serrate on both margins; caudal rounded; V. 6; caudal 

 portion of the body covered with spiny plates above and below; lateral 

 scutes high. (AGAMYXIS.) 



. Coracoid process armed, forked behind; lateral scutes meeting oh 

 the back midway between the dorsal fins and thence backward; 

 barbels reach base of pectoral fins; lateral scutes with their surface 

 spiny, extending to middle of caudal fin; sides of the dorsal and 

 upper surface of the pectoral spine spiny, the lower surface of the 

 latter striate. Deep brown with a light lateral band. D. I, 4; A. 1 1 ; 

 P.I, 5; Lat. 1. 28. (Schomburgk.) castaneo-ventris 179. 



88. Breast entirely covered with skin; upper and lower surfaces of the 

 caudal region with spiny-margined shields; superciliary margin 

 pectinate; two serrate ridges on the premaxillary processes; preop- 

 ercular angle with a serrate crest; two spinous ridges on each side 

 of the dorsal and pectoral spines. Humeral process with an exter- 

 nal series of straight spines. Maxillary barbels not extending to 

 base of pectoral. Black, ventral surface spotted with white; caudal 

 with a light cross-bar. D. I, 5; A. 12; P. I, 5; Lat. 1. 27. (Cope.) 



pectinifrons 180. 



rr. Dorsal spine grooved or serrate in front only; V. 7; caudal peduncle 



without spiny plates above or below; part of the breast with striate 



dermal ossifications; breast very wide. (ASTRODORAS.) 



I. Dorsal spine serrate in front; lateral scutes with accessory spines 



above the median hook; caudal slightly emarginate. 



*Probably an oversight. 



