ICHTHYOLOGY OF VENEZUELA — SCHULTZ 59 



26. No black blotch behind head; interorbital space equal to distance from 



snout tip to rear nostril; dorsal profile of head concave; interorbital into 



head 4.7 to 6.0 and into length of pectoral fin 1.6 to 2.2 times; snout to 



occiput 6.7 to 7.4 and postorbital length of head 7.2 to 9.3, both into 



length of anal fin base. 



da. Posteriorly along midaxis of body and on tail is a bright lemon yellowish 



streak, pale in alcohol; tail rounded behind anal base, tapering to a 



point; postorbital length of head 7.3 to 8.6 into length of anal base; 



snout to occiput into anal base 5.7 to 6.6; interorbital space 1.6 to 2.0 



into longest pectoral fin ray; anal rays 278 to 306. 



Stemopygus pe jeraton, new species 



36. Midaxis of body plain in color and without a pale streak; tail compressed 



behind anal base; postorbital length of head 8.1 to 9.3 into anal fin 



base; snout to occiput into anal base 6.3 to 7.3; interorbital into longest 



pectoral fin ray 1.8 to 2.2; anal rays 256 to 292 (Panama). 



Stemopygus dariensis Meek and Hildebrand 



STERNOPYGUS MACRURUS (Bloch and Schneider) 



Gymnonotus macrurus Bloch and Schneider, Systema ichthyologiae, p. 522, 



1801 (Brazil). 

 Stemopygus carapus Peters, Monatsb. Akad. Wiss. Berlin, 1877, p. 473 (San 



Fernando de Apure, Venezuela)— Sachs, Aus den Llanos, 1879, p. 279 (Apure). 

 Stemopygus macrurus Eigenmann and Allen, Fishes of western South America, 



p. 313, 1942 (Orinoco). 



U.S.N. M. No. 121574, 11 specimens, 94 to 210 mm. in total length, from Rio 

 Gudrico and tributaries between San Sebastian and San Casimiro, L. P. Schultz, 

 G. Zuloaga, Roger Sherman, and William Phelps, Jr., May 12, 1942. 



U.S.N. M. No. 121573, 2 specimens, 250 and 260 mm. in total length, from the 

 Rio San Pedro at bridge, south of Mene Grande, March 20, 1942. 



U.S.N.M. No. 121577, a specimen, 378 mm., from Rio San Juan at bridge, 

 south of Mene Grande, March 20, 1942. 



U.S.N.M. No. 121575, a specimen 443 mm., Rio Motatdn at bridge, 22 km. 

 north of Motatfin, March 17, 1942. 



U.S.N.M. No. 121576, 6 specimens, 125 to 237 mm. and 1 480 mm. to end of 

 anal (tail regenerating), Rfo Negro below mouth of Rio Yasa, March 2. 1942. 



The following measurements were made on a specimen 377 mm. in 

 total length from the Rio San Juan, collected March 20; the data are 

 expressed in hundredths of the length to end of anal fin (which is 

 316 mm.): Length of anal fin base 83.8; head 16.3; snout 5.38; eye 

 1.04; interorbital 4.05; postorbital length of head 9.97; snout to anus 

 9.96; snout to anal origin 16.1; anus to anal origin 7.00; longest 

 pectoral ray 6.42; longest anal ray 4.11 ; snout to occiput 9.97; greatest 

 depth 13.1; depth of head through eyes 6.17; distance from anterior 

 to posterior nostril 2.03; eye to posterior nostril 2.38; width of gill 

 opening 4.68; snout to rictus 2.85; snout to end of maxillary 3.16; 

 snout to pectoral insertion 15.7; length of tail beyond anal 19.9. 



Anal rays 277 and pectoral rays iii,ll-iii,12. 



