224 CALIFORNIA ACADEMY OP SCIENCES. 



nn. Caudal emargiuate; 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. (Amblydoras.) 



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 



hiimeral process. Lateral jjlates almost entirely covered with 



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



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



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. loeddelUi 177. 



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



(Centrochir.) crocodiU 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.) 



s. Coracoid process armed, forked behind; lateral scutes meeting on 

 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 jiectoral spine spiny, the lower surface of the 

 latter striate. Deep brown with a light lateral band. D.I,4;A. 11; 

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



ss. 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 spinoiis 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.) 



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



above the median hook; caudal slightly emarginate. 



*Probably an oversight. 



