752 THE MAMMOTH CAVE AND ITS INHABITANTS. 
caves, and one may yet be found; but how the present form be- 
came a cave dweller is difficult of explanation, as its nearest allies 
are certain species of Idotea which are all marine, with the excep- 
tion of two species: J. entomon, living in the sea and also in the 
depths of the Swedish lakes, as discovered by Loven, the distin- 
guished Swedish naturalist, while a species representing this has 
been detected by Dr. Stimpson at the bottom of Lake Michigan. 
Our cave dweller is nearly allied to Idotea, but differs in being 
blind, and in other particulars, and may be called Cecidotea sty- 
gia.* (Fig. 132 side view, enlarged ; Fig. 133 dorsal view ; b, in- 
ner antenna; ¢, ist leg.) It was found creeping over the fine 
sandy bottom, in company with the Campodea, in a shallow pool 
of water four or five miles from the mouth of the cave. 
This closes our list of known articulates from this and other 
caves in this country, the result of slight explorations by a few in- 
dividuals. The number will be doubtless increased by future re- 
search. It is to be hoped that our western naturalists will thor- 
oughly explore all the sinks and holes in the cave country of the 
western and middle states. The subject is one of the highest in- 
terest in a zoological point of view, and from the light it throws on 
the doctrine’ of evolution. Professor Schiddte, the eminent Danish 
zoologist, has given us the most extended account of the cave 
fauna of Europe, which has been translated from the Danish into 
the Transactions of the Entomological Society of London (new 
series vol. 1, 1851). 
He examined four caves; namely, that of Adelsberg, the Mag- 
dalena and Luege caves, all in the neighborliood of Adelsberg, 
> Generic characters. Head large, much thicker than‘the body, and as long as broad; 
subcylindrical, rounded in front. No eyes. First antenne slend , 8-jointed (2d anten- 
ne broken o: . Abdomi l seg t lidated into one piece. ffers chiefly from 
Idotea, to which it is otherwise closely allied, by the 8-jointed (instead of 4-jointed) Ist 
(inner) antenne, the very large head, and by the absence of any traces of the three ba- 
sal segments of the abdomen usually present in Idotea. 
sm e white: tegument thin, the viscera appearing 
a as segment, and a little more than twice as long. 
enn minute, slender, the four basal joints of nearly equal length, though the 
i ‘ smaller than 
thers, being one-half as thick and two-thirds as long as either of the four basal joints; 
sof ints giving rise to two or three hairs; terminal joint 
ending Ina more distinct knob, and bearing five hairs. e : i 
tinct, sutures deeply incised; edges of segments pilose; 
aajt with a very slight median projection; the entire pair of gills do not reach to 
e end of the abdomen, and the inner Ig iverge posteriorly. Legs long and slen- 
lst pair shorter, but no smaller than the second. Length .25 inch, 
