320 Field Museum of Natural History — Zoology, Vol. X. 



b. Body posteriorly with 6 to 8 dark cross-bars, present in both 

 sexes. irideniiger, p. 320. 



bb. Body in females plain, no cross-bars, male with very indistinct 

 cross-bars. tridentiger cana, p. 321. 



aa. First produced ray of intromittent organ without a recurved 

 spur below its apex. 



c. First produced ray of anal anteriorly serrate below apex, and 

 bearing a hook at apex directed downward and forward, the 

 anterior branch of the second produced ray ciuved forward at 

 apex; a dark area at base of anterior rays of anal. 



dariensis, p. 321. 



cc. Intromittent organ without hooks or serrations, the apex c\irved 



forward; a dark area about vent. panamensis sp. nov., p. 322. 



57. Priapichthys tridentiger (Garman). 



Gambusia tridentiger Garman, Mem. Mus. Comp. Zool., XIX, 1895, 



89, PI. IV, fig. 10, teeth (Isthmus of Panama); Regan, Biol. Cent. 



Amer., Pisces, 1907, 95. 

 Priapichthys tridentiger Regan, Proc. Zool. Soc. London, 1913, 992. 



Head 3.55 to 4; depth 3.1 to 5.35; D. 7 or 8; A. 9 or 10; scales 28 to 30. 



Body compressed; profile straight from snout to nape, then convex 

 to dorsal; head flat above; snout short, 3.75 to 4.3 in head; eye 2.85 to 

 3.34; interorbital 1.9 to 3; mouth small, cleft reaching about one-third 

 the distance to eye; teeth in jaws pointed, in bands, the outer series 

 somewhat enlarged; scales moderate, cycloid, extending forward to 

 eyes; caudal peduncle strongly compressed, its least depth 1.45 to 2 in 

 head; origin of dorsal in female over the posterior rays of the anal and 

 about equidistant from posterior margin of eye and tip of caudal, or 

 sHghtly nearer the former, in the male its origin is about midway between 

 posterior margin of eye and base of caudal; caudal fin roimded; anal 

 fin in female inserted somewhat nearer base of caudal than posterior 

 margin of eye, its posterior margin concave at least in large examples; 

 in the adult male the anal fin is inserted notably nearer tip of snout than 

 base of caudal, the longest produced ray failing to reach base of caudal 

 by about an eye's diameter, 2 to 2.3 in length of body; the apex of the 

 intromittent organ curved forward, the first produced ray with a spur a 

 short distance below its apex which is directed downward and forward; 

 ventral fins rather small, reaching vent in female, and past origin of anal 

 in the male; pectoral fins reaching slightly past base of ventrals, 1.2 to 

 1.9 in head. 



Color of female olivaceous; scales with pale margins, next to the 

 margins is a dark area formed by dusky points; sides of caudal portion 



