222 CALIFORNIA ACADEMY OF SCIENCES. 



ANALYSIS OF THE SPECIES OF DORAS.* 



a. Prenasal bone not crest-like, sometimes granular, sometimes entirely 

 covered with skin, sometimes with rather prominent spines. 

 6. Pectoral fin consisting of a spine and soft rays. 



c. Dorsal surface with a series of plates between the dorsal and adi- 

 pose fins. Lat. 1. 16-20; a groove extending backward from the 

 fontanel. (LITHODORAS.) dorsalis 161. 



cc. Dorsal surface without plates between the dorsal and adipose fins. 

 d. Dorsal spine serrate on both margins. (DoR,AS=Platydoras.) 

 e. Caudal peduncle naked above and below. 

 /. Lateral scutes 18, decreasing in height backward, their en- 

 tire free surface covered with short spines. D. I, 6; A. 6. 

 V. 6. uranoscopus 162. 



ff. Lateral scutes 26-30. 



g. Fins with round spots; pectoral spine reaching to below 

 third dorsal ray. Fontanel continued as a groove to tip of 

 dorsal plate. Eye 10 in the head. granulosus 163. 



gg. Fins plain, except the caudal; pectoral spine reaching 

 beyond origin of ventrals. Fontanel not continued as a 

 groove. Eye 4 in the head; interorbital flat; postorbital 

 part of the head roof -shaped. Maxillary barbels reaching 

 beyond middle of pectoral spine; postmentals not to pos- 

 terior margin of opercle. Humeral process extending to 

 middle of pectoral spine. Sides of the body grayish violet; 

 each lobe of the caudal fin with a rather broad violet band. 

 Head 4; D. I, 6;A. 13; P. I, 7; V. 7; Lat. 1. 29-30. (Stein- 

 dachner.) longispinis 164. 



ee. Caudal peduncle with plates above and below. 

 h. No lateral band. 



i. Sides and belly spotted with white; lateral plates high, 



with 2 accessory spines above and 2 below the median hook; 



caudal plates spiny. Humeral process reaching to the 



fourth lateral plate, with two series of spines. Maxillary 



barbels reaching to base of pectorals. D. I, 6; A. 11-12; 



V. 6; Lat. 1. 29. albomaculatm 165. 



ii. Sides plain or spotted with dark brown. 



j. Whole surface of the lateral scutes covered with minute 



spines. Black; dorsal fin white, its center black; base of 



anal fin and two posterior rays white. D. I, 6; A. 12; 



P. I, 8; V. 8; Lat. 1. 32-34. (Giinther.) helicophilis 166. 



jj. Lateral plates with ridges radiating from the median 



hook and terminating in a short spine, one above and 



one below the median hook on the middle and posterior 



*.\Jany of the species of this getms are known only from poor descriptions, and the 

 following "key" could, therefore, be made with no degree of satisfaction. 



