68 THE CYPRINODONTS. 



Xiphophorus Hellerii. 



Plate IV. Fig 14, teeth; Plate VIII. Fig. 4, male. 



Xiphophorus Hellerii Heck,, 1S52, Sb. Ak. Wien, I (1848), 291, pi. 8, fig. 1-3 ; Blk., 1860, Cypr., 485, 

 — 1863, Atl., Ill, 140; Troscli., 1865, Wirb. Mex., 104; Gth., 1868, Tr. Zool. Soc. Loud., VI, 485, pi. 87, 

 fig. 2-6; Jor. & G., 1883, B. 16 U. S. Mus., 346. 



Mollienesia {Xiphophorus) hellerii Gtli., 1866, Cat., VI, 349. 



Mollienesia hellerii Gth., 1880, lutr., 617. 



Xiphophorus kelleri Eig., 1893, P. U. S. Mus., XVI, 57. 



B. 5 ; D. 13-14 ; A. 8-10 ; V. 6 ; P. 14 ; LI. 28-29 ; Ltr. 8 ; Vert. 30. 



Moderately elongate, compressed, caudal pedicel deep. Head depressed, 

 less than depth of body, little more than one fourth of the length to the 

 base of the caudal. Snout short, as long as eye, broad, subtruncate ; chin 

 short, steep. Mouth wide, directed upward ; lower jaws longer, loosely 

 joined; upper short, protractile. Outer series of teeth slendei', movable, 

 oar-shaped, hooked ; inner in bands, small, pointed. Eye large, longer than 

 snout in young, two sevenths of head, more than half of interorbital space. 

 Dorsal large, deep, becoming longer in males, originating farther forward 

 than the anal in both sexes. The dorsal origin on the female is nearly mid- 

 way from snout to base of caudal. Anal small, outer angle acute on the 

 female ; modified on the male to form an intromittent organ, the length of 

 which is less than that of the head, and the end of which is barbed with seve- 

 ral hooks. Caudal deep, scaly at the base, longer than the head, on males 

 with the lower third produced into a long pointed appendage that varies 

 greatly in individuals, in cases reaching a length equal to that of body and 

 head. Scales large ; lateral line distinct. Intestine elongate. 



Light olivaceous to yellowish ; cheeks and belly silvery. A frequent 

 marking on the male is a black stripe from the snout, through the eye, 

 along the flank and on the upper edge of the caudal appendage, and an- 

 other stripe from the anal fin along the lower edge of the caudal. Between 

 the stripes the caudal is yellow. The coloration varies excessively ; from 

 reticulations or longitudinal vitta3 to scattered irregular blotches of black over 

 head and body. Fins clouded, or dorsal with small spots irregularly placed 

 or in transverse series. In cases the median band on the flank is blue and 

 separates two yellowish or greenish bands which are bordered by blue above 

 and below. The irregular blotches of black on some specimens are scattered 

 over body, dorsal and caudal. 



The largest male in the collection measures four and three eighths inches. 



Mexico ; Central America. 



