THE CATFISHES OF VENEZUEiLA — SCHUT^TZ 225 



CETOPSORHAMDIA ORINOCO, new species 



Plate 3, A 



Holoiype.—U.S.lSi.M. No. 121214, a specimen 53.5 mm. in standard 

 length, collected by Leonard P. Schultz, March 31, 1942, in the Rio 

 Torbes, 1 km. above Tariba, Orinoco system, Venezuela. 



Paratypes.—IJ.S.'NM. No. 121215, 4 specimens, 32.5 to 51.5 mm., 

 taken along with the holotype and bearing the same data. 



Description.— Based on the holotype and paratypes listed above. 

 Detailed measurements of the holotype and a paratype, expressed 

 in hundredths of the standard length, are recorded below, respectively. 

 Standard length (in mm.) 53.5 and 33.7. 



Length of head to end of operculum 25.4 and 29.1; width of head 

 across base of pectorals 20.6 and 20.8; greatest depth 14.2 and 14.8; 

 length of snout 10.7 and 11.6; diameter of eye 3.74 and 3.26; distance 

 from eye to posterior nostril 2.42 and 2.38; distance between anterior 

 and posterior nostrUs 3.92 and 3.86; width of interorbital space 6.72 

 and 8.01; postorbital length of head 12.5 and 15.1; total length of 

 adipose fin 22.6 and 24.3; height (greatest) of adipose fin 3.92 and 

 4.75; least depth of caudal peduncle 8.60 and 9.20; length of caudal 

 peduncle from anal base to midbase of caudal fin 23.6 and 24.0; 

 length of first ray of dorsal fin 18.5 and 22.6; length of first ray of 

 pectoral fin 17.9 and 23.1; longest ray of pelvic fin 14.6 and 18.4; 

 longest branched ray of anal fin 14.6 and 16.3; longest ray of upper 

 lobe of caudal fin 21.9 and 24.6; longest ray of lower lobe of caudal 

 fin 24.9 and 27.3; length of shortest midcaudal fin rays 12.3 and 

 15.7; distance from tip of snout to dorsal origin 37.9 and 40.0; snout 

 to anal origin 67.3 and 68.0; snout to adipose origin 70.4 and 70.0; 

 snout to pelvic insertion 44.5 and 45.1; snout to pectoral insertion 

 23.7 and 26.7; dorsal origin to adipose origin 34.2 and 30.9; anus to 

 anal origin 14.0 and 13.7; length of maxillary barbel 28.6 and 37.1; 

 length of outer mental barbel 15.1 and 20.5; length of inner mental 

 barbel 11.6 and 13.4; length of anal base 13.1 and 13.7. 



Head depressed anteriorly, body compressed posteriorly; snout 

 bluntly rounded, projecting beyond the subterminal mouth; villiform 

 teeth in a band on premaxQlaries and on dentaries, without posteriorly 

 projecting angles laterally; no teeth on vomer or palatines; nostrils 

 wide apart, the posterior one funnel-shaped near eye, the anterior 

 one near front of snout; a pair of maxillary barbels, lying in a groove 

 to under eye and extending to opposite four-fifths the length of pec- 

 toral fin ; two pairs of mental barbels, their bases almost in a straight 

 line, the outer pair reaching almost to rear of base of pectoral fin and 

 the inner pair about four-fifths the way to opposite pectoral insertion, 

 eye without a free margin; a thin membrane along margin of shoulder 

 girdle under gill cover; caudal fin deeply concave or forked, but the 



