388 The American Naturalist. [May, 
somewhat turgid. The length of the shell is 1.5 mm. to 1.85 
mm. The aperture is nearly as broad as long. (Call.) 
About 150 examples of this minute mollusk were secured 
during various visits to Mammoth Dome, in Mammoth Cave. 
They were found on the wet surfaces of the old bridge timbers, 
in that portion of the cavern, which have remained undisturbed 
for fifty or more years. Growing on these in great tufts or 
masses, forming a shaggy mantle that enveloped the great tim- 
bers throughout their length, was a species of Rhizomorpha, a 
peculiarly modified and sterile form of basidiomycetous fungus ; 
in the midst of this fungous growth occur numerous examples 
of this shell. Occasional specimens are found on the under 
surfaces of the wet rocks of this part of the cave, but none have 
ever been taken in a dry situation in the Dome. The constant 
dripping of water, which in the wet season is a stream falling 
from the roof 150 feet above, keeps the rocks and old timbers, 
with their fungous growths, all continually wet, and, except 
the utter darkness, makes the pae a desirable home for “a 
well brought up’ ” Carychium. 
This species is much smaller in ih relative size of the aper- 
ture and length of shell than its nearest ally Carychium exiguum 
Say. But it isa much heavier shell, far more rounded and 
shining than that form. Carychium exiguum from Indiana and 
and New York, with which I have compared it, is a much 
slenderer shell. Compared with the doubtful Carychium exile 
Lea it has a broader body whorl, is more conical, and has no 
striations, which are marked features of that form. Compared 
with the so-called Carychium occidentale the shape and size of 
the body whorl are different, the form of the lip and the curva- 
ture of the outer lip above are distinct. Since our form seems 
to be constant in all these differences it has been decided to 
present it under the name of Carychium stygium. Specimens 
may be seen in the Academies of Natural Sciences of Philadel- 
phia and Cincinnati, and in the United States National Mu- 
seum. The types are in the Call Collection at the Indiana 
State University, Bloomington. 
The remainder of the new forms are plants, and but a brief 
mention will be made of them. Several of the lower fungi 
