264 CALIFORNIA ACADEMY OF SCIENCES. 



XLV. Trachelyopterus. 



Trach.elyopteru8 Cuv. & Val. Hist. Nat. Poiss. xv, 220, 

 pi. 438, 1840 (coriaceus). 



Type: Trachelyopterus coriaceuH Cuv. & Val. 



Adipose fin none. Ventral fins of six rays, anal of 

 moderate length. Barbels 6, those on the chin disposed 

 in two series. Bones of the head exposed, granular. 

 Fontanel oval. Dorsal plate coalesced with the occipital 

 process. Humeral process present. Gill-membranes con- 

 fluent with the skin of the isthmus. Teeth villiform, 

 none on the vomer. 



204. Trachelyopterus coriaceus. 



Trachelyopterus coriaceus Cuv. & Val. 1. c. (Cayenne); Gttnther, 

 Cat. Fish. Brit. Mus. v, 198, 1864 (copied); Eigenm. & Eigenm. 

 Proc. Cal. Acad. 2d Ser. i, 157, 1888 (Obidos; Porto do Moz). 



Habitat: Amazon; Cayenne. 



Body short and compressed. Head short, its width 

 and depth equal to its length; profile steep, snout trun- 

 cate, the lower jaw entering the profile; bones of the 

 head and the humeral process finely granular. 



Eye small, round, 6 in the head, 3h in the interorbital. 



Maxillary barbels reaching about to tip of humeral 

 process; mental barbels about half as long as the head, 

 the postmentals somewhat longer than the maxillary bar- 

 bels. 



Teeth villiform, in narrow bands. 



Distance of darsal spine from snout o-Sh in the length ; 

 dorsal spine weak, terete, its anterior margin smooth, 

 its posterior with short teeth; its height little less than 

 the head. 



Caudal obliquely rounded. Ventrals reaching the 

 anal. 



Pectoral spine smooth on its outer margin, short teeth 

 on its inner margin, 1 in the head. Humeral process 

 extending a little past the middle of the pectoral spine. 



