The Scyphophori, Haplomi, and Xenomi = 419 
the southern lowlands, gutters and even sewers included. It 
brings forth its brood in early spring. Viviparous and her- 
bivorous with modified anal are the species of Pecilia, abundant 
throughout Mexico and southward to Brazil; Mollienesia very 
similar, with a banner-like dorsal fin, showily marked, occurs 
from Louisiana southward, and Xzphophorus, with a sword- 
shaped lobe on the caudal, abounds in Mexico; Characodon and 
Goodea in Mexico have notched teeth, and finally, Heterandria 
contains some of the least of fishes, the handsomely colored 
males barely half an inch long. 
In Lake Titicaca in the high Andes is a peculiar genus (Ores- 
tias) without ventral fins. Still more peculiar is Empetrichthys 
merriamt of the desert springs of the hot and rainless Death 
Valley in California, similar to Orestias, but with enormously 
enlarged pharyngeals and pharyngeal teeth, an adaptation to some 
unknown purpose. Fossil Cyprinodonts are not rare from the 
Miocene in southern Europe. The numerous species are allied 
to Lebias and Cyprinodon, and are referred to Prolebias and 
Pachylebias. None are American, although two American extinct 
genera, Gephyrura and Proballostomus, are probably allied to this 
group. 
Amblyopside.—The cave-fishes, Amblyopside, are the most 
remarkable of the haplomous fishes. In this family the vent is 
Fig. 330.—Dismal Swamp Fish, Chologaster cornutus Agassiz. Supposed ancestor 
of Typhlichthys. Virginia. 
placed at the throat. The form is that of the Peciliide, but 
the mouth is larger and not protractile. The species are vivip- 
arous, the young being born at about the length of a quarter of 
an inch. 
In the primitive genus Chologaster, the fish of the Dismal 
Swamp, the eyes are small but normally developed. Cholo- 
gaster cornutus abounds in the black waters of the Dismal Swamp 
