68 THE CYPRINODONTS. 
Xiphophorus Hellerii. 
Plate IV. Fig, 14, teeth; Plate VIII. Fig. 4, male, 
Xiphophorus Hellerii Heck., 1852, Sb. Ak. Wien, I (1848), 291, pl. 8, fig. 1-3; Blk., 1860, Cypr., 485, 
— 1863, Atl., III, 140; Trosch., 1865, Wirb. Mex., 104; Gth., 1868, Tr. Zool. Soc. Lond., VI, 485, pl. 87, 
fig. 2-6; Jor. & G., 1882, B. 16 U.S. Mus., 346. 
Mollienesia (Xiphophorus) hellerti Gth., 1866, Cat., VI, 349. 
Mollienesia hellerti Gth., 1880, Intr., 617. 
Xiphophorus kelleri Big., 1893, P. U. 8. Mus., XVI, 57. 
B. 5; D. 13-14; A. 8-10; V.6; P. 14; Ll. 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 slender, 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 vittee 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. 
