The Scyphophori, Haplomi, and Xenomi 199 
belong to Fundulus, a genus widely distributed from Maine 
to Guatemala and north to Kansas and southern California. 
Fundulus majalis, the Mayfish of the Atlantic Coast, is the 
largest of the genus. Fundulus heteroclitus, the killifish, the 
most abundant. Fundulus diaphanus inhabits sea and lake 
Fic. 158.—Death Valley Fish, Empetrichthys merriami Gilbert. Amargosa Desert, 
Cal. Family Peciliide. (After Gilbert.) 
indiscriminately. Fundulus stellifer of the Alabama is beauti- 
fully colored, as is Fundulus zebrinus of the Rio Grande. The 
genus Zygonectes includes dwarf species similar to Fundulus, 
and Adinia includes those with short, deep body. Goodea 
atripinnts with tricuspid teeth lives in warm springs in Mexico, 
Fic. 159.—-Sword-tail Minnow, male, Xiphophorus helleri Heckel. The anal fin 
modified as an intromittent organ. Vera Cruz. 
and several species of Goodea, Gambusia, Pecilia, and other 
genera inhabit hot springs of Mexico, Central America, and 
Africa. The genus Gambusia, the top-minnows, includes nu- 
merous species with dwarf males having the anal modified. 
Gambusia affinis abounds in all kinds of sluggish water in 
