192 PROCEEiDINGS OF THE NATIONAL MUSEUM vol.94 



above Lago Maracaibo, May 1, 1942, 3 examples, 170 to 183 mm.; 

 U.S.N.M. No, 121186, cafio half a mile west of Sinamaica, March 11, 

 1942, 2 specimens, 141 and 155 mm.; U.S.N.M. No. 121185, Rio 

 Palmar at bridge, 70 km. southwest of Maracaibo, taken March 6, 

 1942, 3 examples, 169 to 177 mm.; U.S.N.M. No. 121187, Ci6naga del 

 Guanavana, about 10 km. north of Sinamaica, March 11, 1942, 3 

 specimens, 32, 136, and 146 mm.; U.S.N.M. No. 121184, Rio Negro 

 below mouth of Rio Yasa, March 2, 1942, 4 examples, 138 to 172 

 mm.; U.S.N.M. No. 121211, Rio Apon, about 35 km. south of Rosario, 

 Maracaibo Basin, February 26, 1942, 17 specimens, 124 to 176 mm.; 

 U.S.N.M. No. 121212, Rio Socuy, 3 km. above mouth, February 24, 

 1942, 57 examples, 59 to 220 mm. 



Description. — Based on the holotype and paratypes. Detailed 

 measurem.ents were made on the holotype and two paratypes, data 

 for these being expressed in hundredths of the standard length and 

 recorded below, first for the holotype, then for the two paratypes in 

 parentheses, respectively. Standard length (in mm.) 215 (162; 101). 



Length of head to tip of supraoccipital process 30.2 (28.9; 30.5); 

 length of head to end of gill cover 23.2 (22.0; 23.7); greatest depth of 

 body 19.4 (17.3; 17.8); width of head at base of pectorals 15.1 (14.1; 

 14.6); length of snout 9.86 (10.2; 9.52); diameter of eye 5.11 (4.37; 

 6.44); diameter of bony orbit 5.58 (5.86; 7.23); width of fleshy inter- 

 orbital 7.95 (8.88; 7.03); width of bony mterorbital space 6.65 (6.30; 

 5.64); distance from eye to posterior nostril 4.65 (4.63; 3.96); distance 

 between posterior and anterior nostrils 2.84 (3.08; 3.07); postorbital 

 length of head 9.30 (7.90; 9.12); total length of adipose fin 3.91 (4.13; 

 3.77); greatest height of adipose fin 4.88 (5.74; 6.44); least depth of 

 caudal peduncle 7.44 (7.78; 7.23); length of caudal peduncle 19.3 

 (19.8; 19.9); length of first srniple ray of dorsal 25.4 (29.9; 35.0); 

 length of pectoral spine 19.5 (21.3; 21.8); length of longest pelvic fin 

 ray 18.0 (20.2; 20.3); length of longest anal ray 14.1 (15.5; 14.9); 

 length of upper caudal fin lobe 33.0 (37.0; 35.2) ; length of lower caudal 

 fin lobe 28.2 (30.9; 32.8); length of shortest midcaudal fin rays 8.93 

 (9.38; 9.12); distance from tip of snout to dorsal fin origin 29.8 (34.4; 

 34.9); distance from snout to anal origin 72.6 (78.4; 71.8); snout to 

 adipose origin 51.6 (46.6; 52.1); snout to pelvic insertion 44.6 (42.0; 

 42.6); snout to pectoral insertion 22.1 (20.3; 23.0); snout to anus 49.0 

 (47.1; 47.0); anus to anal origin 24.2 (26.9; 23.7); length of maxillary 

 barbel 102.0 (136.0; 156.0); length of outer mental barbel 30.0 (38.9; 

 42.1);lengthof inner mental barbel 16.7 (21.0; 24.8); width of base of 

 supraoccipital process 4.65 (4.93; 4.96); length of supraoccipital 

 process from rear end of occipital fontanel to its tip 5.58 (5.86; 7.23). 



Counts were made as follows: Dorsal rays i, 6 (i. 6; i, 6); anal v, 6 

 (v, 7; V, 7); pectoral I, 11 (I, 11; I, 10); pelvic always I, 5; branched 

 rays of caudal fin 15 or 16 usually 16; number of gill rakers on first gill 



