28 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
Dendrocceltjm perccectjm Pack. 
Dendroccelum perccecum Pack., Zoology, 142, 1879. f-J'f. 
Fig. 6. 
A cave Pla- 
narian. Den- 
drocoelum per- 
ccecum Pack. 
This interesting form was first observed at different points in Mammoth Cave. It 
is entirely white, and after repeated examinations of living specimens we could see no 
eye-specks, the creatures being totally blind. In form it is oval-lanceolate, the head end 
at times scarcely more pointed than the posterior end, though it is sometimes angular in 
front, a lobe-like process extending out on each side of the head, as observed in other 
species of the genus. It extrudes a large square-tipped proboscis, the end being orbicu¬ 
lar, and then suddenly withdraws it. Length, 5 mm . 
This was not uncommonly found under stones in a stream we have called Shalers 
Brook, in the water in Gothic Avenue, in Richardson’s Spring, Mammoth Cave, and 
also in water in Diamond Cave. It is quite active in its habits, moving freely about like an ordinary 
Dendroccelum lacteum. 
LUMBRICUS sp. 
Earth-worms were not uncommon, though of small size, in Mammoth, Diamond, and other 
caves; living especially in the damper situations. 
MOLLUSCA. 
Numerous Helices were found in all the smaller caverns, but as none seemed to be specially 
bleached or to differ from out-of-door forms, no attention has been given to them. Still, it would 
be desirable to pay an attentive examination to those living in caves, as there may be found, as 
have occurred in European caves, some individuals whose eyes have been modified by a cave life. 
CRUSTACEA. 
Cauloxenus stygius Cope. PI. I, figs. 1, la, lb. 
Cauloxenus stygius Cope, Amer. Naturalist, vi., 412, July, J£S83r% 8 - 
This Lerntean is said by Cope to be a parasite of the blind-fish, and to live attached by the 
disc to the inner edge of the upper lip. “ This position being maintained, it becomes a favorable 
one for the sustenance of the parasite, which is not a sucker or devourer of its host, but must feed 
on the substances which are caught by the blind-fiSh and crushed between its teeth. The frag¬ 
ments and juices expressed into the water must suffice for the small wants of this Crustacean.” 
Cope describes and figures the two egg-pouches, but these were not present in the specimen we 
had for examination. Whether Mr. Cope’s genus Cauloxenus really differs from Achtheres or not, 
we are not prepared to say. “ The character,” he remarks, “ which distinguishes it from its allies 
is one which especially adapts it for maintaining a firm hold on its host, i. e., the fusion of its jaw- 
arms into a single stem.” In the specimen we figure, however, the arms are much as in Achtheres 
carpenteri, separate for a part of the way, but not so widely so as in A. carpenteri. The body is 
short and thick, the head oval-rounded, the “arms” short and thick, and of the same length as the 
head. The shape of the rest of the body in my specimen is irregular. The reader is, for further 
details, referred to our camera figures. 
COPEPODA. 
Canthocampttjs cavernarum Pack. PI. I, figs. 2, 2a, 2b. 
Canthocamptus cavernarum Pack., Zoology, 297, Pig. 238, 1879. 
Body slender, cylindrical, tapering slowly to the end of the body. Carapace not wider than 
the segment next behind it, but about three and a half times longer, and equal to the combined 
length of the succeeding five segments; sixth and seventh segments of the body the longest, the 
eighth being but little shorter than the seventh. The hinder edge of each segment except the last 
