SOUTH AMERICAN NEMATOGNATHI. 263 



head exposed, granular. Dorsal plate coalesced with the 

 occipital process. Humeral process present. Gill-mem- 

 branes confluent with the skin of the isthmus. Teeth 

 villiform, none on the vomer. 



203. Trachelyopterichthys taeniatus. 



Trachelyopterus tceniatus Kiier, SB. Ak. Wien, xxvi, 434, pi. viii, 



fig. 26, 1857 (Eio Guapore); Giinther, v, 198, 1864 (copied); 



Steindachner, Flussf. Siidamerika's, iii, 4, 1881 (Rio Guapore; 



Teffe). 

 Trachelyopterichthys tceniatus Bleeker, Nederl. Tijdschr. Dierkunde, 



i, 111, 1863 (name only); Eigenm. & Eigenm. Proc. Cal. Acad. 



2d Ser. i, 157, 1888 (Teffe). 

 Habitat: Solimoens and tributaries. 



Body elongate, compressed. Head short and wide, its 

 width greater than its length, its depth slightly less than 

 its length; bones of the head exposed, coarsely granular; 

 sutures distinct; dorsal plate widely forked behind. Fon- 

 tanel elongate. 



Eye small, 5 in the head, 3J in the interorbital. 



Maxillary barbel reaching tip of humeral process; 

 mental barbels short, little longer than the eye; post- 

 mentals reaching base of pectorals. Snout short, rounded; 

 jaws equal; teeth all villiform. 



Distance of dorsal spine from tip of snout 4-4 J in the 

 length; dorsal spine sharply granular in front, smooth 

 posteriorly; its length 1J in the head. 



Caudal obliquely rounded. 



Base of the anal very long, 2-J2| in the length. 



Ventrals very large, reaching the anal. 



Pectoral spine somewhat longer than the head, gran- 

 ular on its lower, finely stirate on its upper surface. Hu- 

 meral process extending beyond middle of pectoral spine. 



Pectoral pore present. 



Coffee-colored, all the fins dusky, especially near their 

 tips. 



Head6|; depth 5J-6J; D - I, 4 ; A - 53; P. I, 8; V. 15-16. 



Three specimens .13-. 15 m. Teffe. L. Agassiz. 



