SOUTH AMERICAN NEMATOGNATHI. 393 



Body heavy, compressed, everywhere deeper than 

 wide. Head angular, profile steep and straight; occipi- 

 tal terminating in an elevated triangular process. Sides 

 of the head vertical, eyes lateral. Interorbital slightly 

 convex; a shallow groove extending from nares forward; 

 all the bones of the head hispid, the spines being strong- 

 est on the occipital process. 



Orbit 2 in the snout, 5 in the head, 2 in the inter- 

 orbital. 



Snout pointed; lower surface of the head naked except 

 a triangular area below the eye. Surface of clavicle and 

 coracoid hispid, the ventral surface betw.een them and 

 the ventrals closely covered with 3 series of plates; a 

 larger triangular plate between bases of ventral fins; a 

 Y-shaped naked area extending from the vent forward 

 and on either side of the interventral triangular plate. 



Tail flattened above and below; all the plates hispid. 



Distance of dorsal fin from tip of snout 2-2| in the 

 length; dorsal spine high, about one diameter less than 

 length of head. 



Caudal emarginate. Pectoral extending little beyond 

 origin of ventrals, the ventrals not to the anal fin. 



Light brown; a narrow dusky bar extending from eye 

 to base of caudal. 



Head 3; D. I, 7; A. 6; V. 6; P. 1, 6; Lat. 1. 23-24, 



Twenty specimens .03-.045 m. Santa Cruz. Dom 

 Pedro II. 



340. Otocinclus vestitus. 



Otocinclus vestitus Cope, Proc. Acad. Nat. Sci. Philad. 1871, 283, pi. 



iv, fig. 2 (Ambyiacu River); Eigenm. &Eigenm.l. c. 

 Habitat: Ambyiacu River. 



