19. PSAMMODISCUS. 457 



not united with the anal. Scales very small, imbricate, cycloid ; 

 the lateral line is very gently curved above the pectoral ; a second 

 lateral line runs from above the eye, along and near the dorsal pro- 

 file, to behind the middle of the dorsal fin. Uniform brownish lead- 

 coloured. 

 California. 



a. Eight and a half inches long. San Francisco. Presented by Dr. 

 W. 0. Ayres. 



We dedicate this species to the excellent Californian ichthyologist, 

 whose discoveries only recentlj' became acccs&xble to iis. The speci- 

 men, which appears to us specifically distinct from P. ccenosa, formed 

 part of a splendid collection, which was nearly entirely destroyed 

 during its transmission to Europe. 



19. PSAMMODISCUS. 



Eyes on the right side. Mouth rather narrow, the length of the 

 maxiUaiy being one-third or nearly one-third of that of the head ; 

 jaws more developed on the coloured side than on the blind. Teeth 

 minute, in a single series or in an exceedingly narrow band ; vomerine 

 or palatine teeth none. . The rays of the posterior half of the dorsal 

 and anal fins are branched ; the dorsal fin commences on the snout. 

 Scales small ; lateral line with a strong curve anteriorly. Gill-mem- 

 branes broadly united at the throat ; gill-rakers lanceolate. Bran- 

 chiostegals six. 



1. Psammodiscus ocellatus. 

 D. 64. A. 54. L. lat. 80. 



The height of the body is contained once and two -thirds in the 

 total length (without caudal), the length of the head thrice and a 

 half. Head about as high as long. Scales cycloid. Snout very 

 obtuse, as long as the eye, the diameter of which is somewhat less 

 than one-fourth of the length of the head. Eyes separated by a very 

 narrow ridge ; their front margins nearly on the same level. Gill- 

 rakers slender, one-third as long as the eye, closely set. The dorsal 

 fin commences between the maxillaries and is continued on to the root 

 of the caudal ; its anterior rays have their tips prolonged beyond the 

 membrane, the longest rays being in the posterior third of the fin, 

 where they are one-half the length of the head. Anal spine present. 

 Caudal fin rounded, one-fifth of the total length. Ventral fin veiy 

 broad, a Kttle shorter than the pectoral. Brownish-olive, finely 

 marbled and spotted with brown ; a deep-brown ocellus, edged with 

 whitish, immediately below the middle of the straight portion of the 

 lateral line ; another similar but less distinct occUus above the lateral 

 line, behind the curve. Vertical fins irregularly spotted and dotted 

 with brown and white. 



Hab. ? 



a-d. From 32 to 42 lines long. 



