THE CATFrSHES OF VENEZUELA — ^SlCHULTZ 255 



This species was taken in a mountain stream in very swiftly flowing 

 water among gravel and rubble. 



Named Orinoco in reference to the river system in which it was 

 collected. 



PSEUDOCETOPSIS PLUMBEUS MOTATANENSIS, new subspecies 



Plate 5, B 



Holotype. — U.S.N.M. No. 121265, a specimen 146.5 mm. in standard 

 length, collected by Leonard P. Schultz, March 25, 1942, in the Rio 

 Motatan, 4 km. above Motat^n. 



Paratypes (all collected by L. P. Schultz).— U.S.N.M. No. 121268, 

 2 specimens, 113 and 160 mm., collected along with the holotype and 

 bearing the same data; U.S.N.M. No. 121266, an example 57 mm. in 

 standard length, from the Rio San Juan at the bridge, south of Mene 

 Grande, Motatan System, March 20, 1942; U.S.N.M. No. 121267, 

 2 specimens, 67 and 81 mm., from the Rio Motatan, 8 km. below 

 Motatan, March 24, 1942; U.S.N.M. No. 121269, 5 examples, 57 to 

 113 mm., from the Rio Motatan at the bridge 22 km. north of Motatan, 

 March 17, 1942. 



Description. — Detailed measurements made on the holotype and 

 two paratypes, expressed in hundredths of the standard length, are 

 recorded below, respectively, first for the holotype, then in parentheses 

 for the paratypes. Standard length (m mm.) 146.5 (113; 57). 



Length of head 25.2 (25.2; 28.4); greatest depth 21.5 (19.9; 20.5); 

 length of snout 7.16 (7.52; 7.19); diameter of eye 2.46 (2.65; 4.20); 

 interorbital space 10.2 (9.30; 10.0); postorbital length of head 17.1 

 (17.3; 17.5); distance between anterior pair of nasal openings 5.46 

 (5.13; 5.61); distance between posterior pair of nasal openmgs 4.10 

 (3.81; 4.74); tip of snout to dorsal origm 33.5 (32.7; 35.4); snout to 

 anal origin 58.4 (55.8; 60.2); snout to pectoral insertion 23.2 (23.4; 

 25.4); snout to pelvic insertion 44.1 (41.6; 44.2); snout to anus 53.9 

 (53.2; 57.4); length of maxillary barbel 9.56 (12.8; 13.9); length of 

 anterior mental barbel 7.85 (9.74; 11.9); length of outer or posterior 

 mental barbel 8.53 (10.7; 12.3) ; length of anal fm base 30.7 (30.6; 31.6) ; 

 length of caudal peduncle 13.6 (13.7; 14.4); least depth of caudal 

 peduncle 11.1 (11.3; 11.9); length of first or simple ray of dorsal fin 

 21.9 (30.5; 21.8); length of first or simple ray of pectoral fin 16.1 

 (20.9; 16.0); length of longest or first branched ray of dorsal fin 17.7 

 (20.3; 18.6); length of longest or first branched ray of pectoral fin 

 14.4 (16.8; 15.3); length of longest branched pelvic ray 9.22 (11.1 

 12.1); length of longest upper ray of caudal fin 20.2 (25.2; 22.3) 

 length of longest lower branched ray of caudal fin 21.9 (24.0; 23.2) 

 length of shortest midcaudal ray 12.3 (13.7 ; 14.2) ; width of head across 

 base of pelvics 18.1 (16.4; 16.8). 



The following counts were made, respectively: Anal rays iii, 24 



