ICHTHYOLOGY OF VENEZUELA — SCHULTZ 41 



Body compressed, deep, greatest depth about 3.5 to 4.2, and head 

 about 3.3 to 3.5, both in standard length; depth of head at joint of 

 mandible much less than postorbital length of head; head longer than 

 greatest depth of body; snout bluntly pointed, projecting more than 

 half its length beyond mandible, shorter than eye, scarcely longer 

 than pupil, contained 5% to 5% in head; eye 3.4 to 4.2 in head; maxillary 

 ending in a triangular point, extending to or a little past joint of 

 mandible, contained about 1.3 or 1.4 in head; mandible pointed, not 

 curved upward at tip, reaching a vertical line through rear edge of 

 posterior nostril when mouth is closed; teeth most minute but very 

 numerous along edges of both jaws, often obsolete in adults; cheek 

 6.6 to 7.1 and postorbital length of head 5.2 to 5.6 in standard length; 

 gill rakers very long and slender and very numerous, increasing in 

 number with increase in length or age; depressed length of dorsal 

 fin 1.5 to 2 in head; the first branched rays of dorsal fin reaching a little 

 past tips of last rays when the fin is depressed; distal margin of dorsal 

 fin truncate or a little concave; caudal fin deeply forked; distal margin 

 of anal fin a little concave, first anal rays longest; first upper ray of 

 pectoral fin longest, tips of pectoral fins reaching past the insertion 

 of pelvics, sometimes to opposite nearly halfway toward tips of pelvics 

 in young specimens; pelvic fins reaching halfway to anal origin in 

 young but scarcely halfway to anus in adults; dorsal fin origin equi- 

 distant between midcaudal fin base and front half of eye; origin of 

 anal fin under middle of base of dorsal fin; axillary scale of pectoral 

 extending out about halfway to tip of pectoral fin; intestine with one 

 main loop. 



Coloration. — In alcohol the adults are straw-colored dorsally, silvery 

 on sides, with a dark brownish streak along middorsal line of back; 

 inside of gill cavity blackish ventrally opposite region of maxillary; 

 all fins translucent-whitish except caudal fin, which is dusky with the 

 black pigment cells more intense on distal part of rays; peritoneum 

 silvery but intestine blackish. In the young a silvery lateral band 

 about as wide as eye anteriorly becomes narrower posteriorly. The 

 most characteristic mark is a small black speck at lower base of 

 caudal fin, with a small cross of X-shaped lines of black pigment 

 more or less embedded; base of anal fin with black pigment spots; 

 tip of snout blackish; middle basal part of each lobe of caudal fin 

 more intensely pigmented than remainder of caudal fin; otherwise 

 coloration is similar to that in adult specimens. 



Eemarks. — This new species would, with some exceptions, trace 

 down through Dr. Hildebrand's key (1943, p. 21) to A. rastralis, but 

 it differs from that Pacific species in having 39 to 41 (usually 40) 

 vertebrae instead of 41 or 42. From A. clupeoides it may be separated 

 by the key on page 38. Named nigra in reference to the black pig- 

 mentation on inside of the gill cavity. 



