DICHOLENE NIGRA. 151 



Snout short, as long as the eye, thick, broad, blunt, scarcely projecting 

 beyond the mouth. Ilimler nostril near the eye; anterior as near the lip, 

 with a groove down and forward. Moutli large ; maxillary not in contact, 

 half as long as the head, becoming wider than the eye backward, with 

 npper, lower, and hinder edges concave. Teeth small, in villiform bands on 

 the jaws, in narrower bands which make a short curve inward at the forward 

 ends on the palatines, and in a small group below the forward end of the 

 vomer. Eye of medium size, as long as the snout or the width of the inter- 

 orbital space, two ninths of the head. Gills four, a slit behind the fourth; 

 laminae short ; rakers stout, longest two thirds as long as the eye, four on 

 the upper and ten to twelve on the lower section of the fust arch. Gill 

 openings wide; mendji-anes not united, free from the isthmus. Eight 

 branchiostegal rays. No iiseudobranchite. No barbels. Opercle with a 

 slender horizontal spine at the upper angle, three fourths as long as the 

 eye ; preopercle with three rather short spines, the median little longer, the 

 spaces separating them about equal. A small spine above the hinder border 

 of each eye. Membranes of dorsal and anal continuous with the base of the 

 caudal. Anterior rays of the dorsal a little longer than those of the anal, 

 longest ray more than one third of the length of the head, first a trifle back- 

 ward of the axil of the pectoral, twentieth nearly above the first anal ray. 

 Each ventral of two rays, which are bound together for a short distance at 

 the base. Caudal of six rays, slender, acuminate, free from dor.sal and anal 

 in greater portion of the length. Upper portion of pectorals as long as the 

 head ; lower pai't with six free rays, rarely seven, the longest of which is one 

 half longer than those in the fin web, or less than one and one half times as 

 long as the head. Scales small, thin, flexible, five or six rows between the 

 lateral line and the dorsal fin. Lateral line near the base of the dorsal, dis- 

 tinct in the anterior two thirds of the length. In specimens of eighteen 

 inches the snout is longer than the eye ; the eye is about one fifth of the 

 length of the head ; the maxillary extends backward of the orbit nearly two 

 thirds of the orbital diameter, the hind margin equalling the length of the 

 eye, and the lower angle being acute. Five or six pyloric caeca, short and 

 thick. Air bladder large. 



Coloration of large individuals black. On the younger ones the bases of 

 the fins appear whitish and the muscular tracts reddish brown. 



Readily distinguished from D. filamcntosa by the small number of free 

 rays in the pectorals. 



