Holmes—A New Subterranean Amphipod. 79' 
tennatus from Hickajaek Cave, Tennessee', Crang onyx vitreus 
from Mammoth Cave, Kentucky, and Gammarus caecus from 
a cave in Cuba. Besides the species here described, the fol¬ 
lowing have been found in wells: Apocrangonyx hicifugus 
ITay from Knox County, Illinois, Stygonectes ftagellatus (Ben¬ 
edict) from San Marcos, Texas, Crangonyx tenuis Smith from 
Connecticut, Eucrangonyx pacJcardii (Smith) from wells in 
Orleans and Few Albany, Indiana, and Eucrangonyx mucro- 
natus (Forbes) from wells in Indiana and Illinois. Gammarus 
propinquus Hay, which has been taken from springs near Mam¬ 
moth Cave, Kentucky, in Missouri, and in West Virginia, is 
probably also to a considerable extent a subterranean form. 
Hone of the species mentioned as coming from wells has thus 
far, I believe, been reported from any other habitat. 
It will be seen that the underground species of Amphipoda 
are quite widely distributed. Many of the species are rathe? 
closely related to forms inhabiting the surface waters of neigh 
boring regions. Gammarus purpurascens , for instance, strongly 
resembles the widely distributed C . limnwus , and Eucran¬ 
gonyx packardii is a close ally of E. gracilis, which occurs in 
most of the northern states east of the Kockv Mountains, differ¬ 
ing from it chiefly in the absence of eyes. Apocrangonyx 
lucifugus , Stygonectes ftagellatus , and the three species of 
Crangonyx found in Forth America, although placed in differ¬ 
ent genera, are not widely different from the species of Eucran¬ 
gonyx living in lakes and streams. NipJiargus antennatus has 
no very close relatives among the surface forms, although it 
belongs to the same family, Gammaridae, which includes the 
other species here mentioned; but there are several species of 
Niphargus , most of which are underground forms, which occur 
in Europe. 
The fresh-v T ater Amphipoda possess a remarkably strong 
proclivity toward an underground life. They are notoriously 
creatures of retiring habits, seeking shaded and protected nooks 
out of reach of fish and other enemies that prey upon them. 
They are, as a rule, negatively phototactic, and they possess a 
strong positive thigmotaxis—two traits that conspire to lead 
them into a subterranean habitat when opportunity offers. 
