248 PROCEEDINGS or THE NATIONAL MTJSiEUM vol.94 



width of the interorbital space in front of the anal fin origin; eight 

 barbels as follows: two pairs of mental barbel'?, the outer pair longest; 

 a pair of large maxillary barbels, with a membrane that conDects with 

 the side of the head opposite the eye, the maxillaiy barbels reaching 

 a little past the middle of the coracoid process; a pair of barbels near 

 outer front corners of the m.outh at base of maxillary barbels on ven- 

 tral surface of snout ; snout broadly rounded anteriorly, with a median 

 indentation ; upper lip composed of four large papillae ; lower lip thin, 

 without papillae, the small gill opening just in front of base of pectoral 

 fin on lower sm-face of body; upper surface of head with a lump at 

 rear tip of supraoccipital, behmd which are two more elongated ridges, 

 then the origin of the dorsal; orbital rims slightly elevated, the inter- 

 orbital space otherwise flattish; eyes very small, the posterior margin 

 of orbit a little closer to tip of snout than to rear tip of supraoccipital; 

 mouth opening equal to interorbital space; two pairs of nostrils widely 

 separated, the anterior ones tubular; caudal fin truncate, the first 

 outer branched ray of lower lobe longest, the upper simple ray short- 

 est; pectoral spine wilh sLx long spines on its inner edge, pectoral spine 

 with a fleshy tip; pelvic spine about two-thirds the length of the first 

 branched ray; dorsal fin connected with body by a membrane to tip of 

 last ray; anal similarly connected by a membrane to the body but not 

 quite to the tip of the last anal ray. 



HOPLOMYZON ATRIZONA PETKOLEUS. new subspecies 



Plate 4, C; Figure 4, a 



Holotype. — U.S.N.M. No, 121070, a specimen 25.3 mm. in standard 

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

 Motatan, 4 km. above Motatan, Maracaibo Basin, Venezuela. 



Paratype. — U.S.N.M. No. 121071, a specimen 24.7 mm. in standard 

 length, taken along with the holotype and bearing the same date. 



Description. — Based on holotype and paratype. Detailed measure- 

 ments of these, expressed in hundredths of the standard length, are 

 recorded, respectively. Standard length (in mm.) 25.3; 24.7; total 

 length 30.9 and 29.5 mm. 



Length of head from tip of snout to posterior tip of supraoccipital 

 26.5 and 27.1 ; width of head at coracoids 26.9 and 26.7; greatest depth 

 of body 12.0 and 12.1; postorbital length of head 14.6 and 14.2; length 

 of snout 11.1 and 10.1; diameter of eye 1.98 and 2.02; width of fleshy 

 interorbital space 7.90 and 7.29; width of gape of mouth 7.90 and 7.70; 

 longest (outer) mental barbel 7.90 and 6.48; length of maxillary barbel 

 measured from its anterior base to its tip 20.5 and 19.4; length of 

 barbel at front corner of upper lip 4.74 and 4.86; distance between 

 anterior nostrils 5.14 and — ; anus to anal origin 14.2 and 15.4; tip of 

 snout to anus 36.3 and 35.6; length of base of dorsal fin from bony 



