The Scyphophori, Haplomi, and Xenomi 201 



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 Pcecilia, abundant 

 throughout Mexico and southward to Brazil; Mollienesia very 

 similar, with a banner-like dorsal fin, showily marked, occurs 

 from Louisiana southward, and Xiphophorus, with a sword- 

 shaped lobe on the caudal, abounds in Mexico ; Characodon and 

 Goodea (see Fig. 53, Vol. I) 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 

 merriami 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. 



Amblyopsidae. The cave-fishes, Amblyopsidce, are the most 

 remarkable of the haplomous fishes. In this family the vent is 



FIG. 161. Dismal Swamp Fish, Chologaster cornutus Agassiz. Supposed ancestor 

 of Typhlichihys. Virginia. 



placed at the throat. The form is that of the Pceciliida, 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 



