256 PROCEEMNGS OE TETE NATIONAL MUSEUM tol. 94 



(iv, 22;iv, 23;iii, 22;m, 22;iv, 22;iii, 23;iii, 23 ; iii, 22 ; iii, 22;iv, 21); 

 dorsal rays i, 6 (i, 6 ; i, 6 ; i, 6 ; i, 6 ; i, 6 ; i, 6 ; i, 6 ; i, 6) ; pectoral rays on 

 ten i, 9-i, 9, on one paratype i, 8-i, 8; pelvics always i, 5 and branched 

 caudal fin rays 15 (15; 15); gill rakers — ( — ; 2-f-7). 



Head bluntly rounded anteriorly, body compressed posteriorly, 

 snout projecting a little beyond the lower jaw; mouth subterminal; 

 gape moderately wide; anterior pair of nostrils at sides of snout a 

 little more separated than the posterior pair, which is situated between 

 the eyes; interorbital space convex; eyes embedded, their margins not 

 free; gill membranes broadly joined to the isthmus; gill openings 

 wide, a little longer below than above base of pectoral fins; gill rakers 

 short, stiff, about 2+6 or 7; maxillary barbels lying in a groove; 

 mental barbels lying in a shallow depression on under side of head; 

 first ray of dorsal and of pectoral considerably produced in the males 

 beyond the branched rays; anal rays of males longer than in fem.ales; 

 anus equal distance from midbase of caudal fin and a little behind 

 rear of eye; caudal fin deeply concave; dorsal truncate or slightly 

 concave posteriorly; pelvics a little rounded and pectorals truncate 

 or rounded; inner sides of pelvics joined and fused with midline of 

 abdomen; caudal peduncle longer than deep; teeth all conical in about 

 three irregular rows on premaxillaries, two on dentaries and an 

 irregular row on vomer, the latter not interrupted in the middle. 



Color. — Grayish to brownish above, paler below, with the sides well 

 supplied with small dark blotches, more or less obscure in some speci- 

 mens; these spots are much less evident in this form than in Orinoco. 

 Caudal fin edged with white on all margins; inside of white posterior 

 margin the caudal fin pigment is intensified considerably; paired fins 

 plain, pale in color, the dorsal grayish; anal with distal half dark, the 

 edge white; peritoneum mostly pale. 



Remarks. — This new species may be separated from all related forma. 

 by means of the key on page 253. It was taken in swiftly flowing 

 water among rubble to coarse gravel. 



Named motatanensis after the stream system in which it was 

 collected. 



Family PYGIDIIDAE 



KEY TO THE GENERA OF PYGIDIIDAE REPORTED FROM VENEZUELA (MODIFIED 

 MOSTLY AFTER EIGENMANN) 



la. Anal fin short with 7 to 11 rays, its origin usually behind, rarely under that 

 of dorsal fin; eyes superior. 

 2a. A pair of nasal barbels; no mental barbels; mandible with considerable 

 anteroposterior extent, teeth extending along less than half its total 

 length; teeth strong; anal short; no mental barbels; opercle and inter- 

 opercle with spines; two barbels at angle of mouth; opercle without a 

 dermal flap; caudal peduncle compressed; anal partly or entirely behind 

 dorsal; pelvics present; outer pectoral ray usually prolonged. 



Pygidium Meyea 



