880 The Fauna of the Nickajack Cave. [November, 
This species forms, in the antenne and slightly purplish color 
and the proportions of the leg-joints, perhaps a nearer approach 
to the genus Asellus than that of Mammoth and Wyandotte 
caves; on the other hand C. stygia approaches Asellus more in 
its shorter, broader body, with the shorter, broader abdomen. It 
seems quite evident that the two species must have descended 
from different species of Asellus. Thus far we know of but one 
species of Asellus, A. communis of Say, from the Middle and 
Northern States; whether there is an additional species in the 
Gulf States from which the present species may have been de- 
rived, remains to be seen, 
The genus Cecidotea differs from Asellus in the larger and 
much longer head, the longer claw of the first pair of feet, the 
much longer telson, and in the rami of the caudal appendages 
being of nearly equal size, while in Asellus one is minute ; it is 
also eyeless. The Asellus dorelit of the Swiss lakes belongs to 
Cecidotea. 
The second crustacean discovered swimming about in the sub- 
terranean stream, was a species of Amphipod belonging to the 
genus Crangonyx, and which may be called Crangonyx anten- 
natus Packard! It isa large purplish species with very long 
antenne, and distinct, well developed black eyes. This genus 
occurs in caves and subterranean wells in Europe and this 
country. 
The form of most decided interest, however, is the blind craw- 
1It is a larger and purplish species; the first antenne very long; the flagellum with 
20-24 joints; the entire antenna being over one-half, and nearly two-thirds as long 
as the body; the last joint of the peduncle being slightly more than half as long as 
the penultimate joint. Compared with C. gracél’s Smith, from Lake Superior, it 
differs in the form of the eyes, the longer and stouter first antenna, the flagellum 
having a greater number of joints, and in the different proportions of the joints of 
the peduncle; the second joint of the latter being much longer than in C. gracidis, 
while the first juint of the scape is much longer, and the second and third joints one- 
third longer in proportion than in C. gracilis. The fourth pair of epimera are unu- 
sually large and nearly square. The telson, together with the caudal stylets is much 
as in C. gracéfis, but the rami are slightly stouter and more polished, and the spinules 
a little stouter. It probably is a little larger species than C. gracilis, the specimens 
being 6-7,mm, in length; the eyes are not so distinct and are only one-fourth as 
large as in C. gracilis. It is very different from C. vitreas Cope, of Mammoth cave, 
and from C. fackardii Smith, differing in its distinct eyes, and larger, more numer- 
ously jointed antennz. 
