MEMOIRS OP THE NATIONAL ACADEMY OF SCIENCES. 19 



At a distance of a mile from the mouth the bliud crayfish, Orconeetes hamulatus Cope, began to 

 he abundant ; their snowy-white forms being- readily distinguished by candle light in the clear water. 



On the land the Pseudotremia eavernarum proved to be common in some places, especially 

 near to bat excrement, where were also found a number of Pselaphid beetles.* 



On examination of the aquatic cave life it appears that of the five kinds of animals found 

 living in the waters of the cave all but one differ decidedly from those of the caves of Kentucky, 

 Indiana, or Virginia. This is a matter of considerable interest from an evolutional point of view, 

 as it shows that these cave forms are the descendants of different out-of-door species from those of 

 the caves to the northward. The Nickajack Cave may be in a different faunal region from the 

 Mammoth or Wyandotte Caves, and thus the bliud crayfish has evidently originated from a different 

 species of Cambarus than that which gave origin to Cambarus pellucidus. Thus, while the condi- 

 tions, such as dryness and temperature, of cave life are much the same throughout the United 

 States, the aucestors of the different cave animals were in many eases of distiuct species, since they 

 belonged to somewhat different zoogeographical areas. 



The first animal to notice, and one not uncommon in the waters of the cave, is a little Isopod 

 crustacean (Cecidotcca nickajaekensis Packard), which is evidently a modified Asellus, or water 

 wood-louse, of the same genus as that so abundant in the caves, subterranean streams, and wells 

 of Indiana and Kentucky. 



This species forms, in the antennae 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 widespread 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 derived, remains to be seen. 



The genus Cecidotaea 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 iu Asellus one is minute; it is also eyeless. 



The second crustacean discovered swimming about in the subterranean stream was a species 

 of Amphipod, belonging to the genus Craugonyx, and has been described as Crangonyx antennatus 

 Packard. It is a large purplish species, with very long antennae, 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 crayfish (Orconeetes hamulatus Cope). 

 It is quite different from C. pellucidus of Mammoth and Wyandotte caves, in .the rostrum, the slender 

 hands, the much broader antennal scale, and in the form of the gonopods, while the whole creature 

 is slightly slenderer than C. pellucidus, though the rudimentary eyes are of the same proportion to 

 the neighboring parts as in the other species. 



Of the two crickets found in Nickajack Cave, there were three small specimens of Hadencecus 

 subterraneus Scudder, which only differed from Mammoth Cave individuals in having rather shorter, 

 thicker maxillary palpi; but this is not even a varietal difference, as the antennae and legs have 

 tljH same proportions. The other cricket is a new species of Ceuthophilus, and has been called 

 Ceuthophilus ensifer Packard. It is very nearly allied to C. stygius of Mammoth Cave, but may be 

 distinguished by the characters given elsewhere. 



CLINTON'S CAVE, UTAH. 



While attached to the United States Geological and Geographical Survey of the Territories 

 in the, summer of 1875, during a visit to Great Salt Lake, my attention was called by Jeter Clinton, 

 esq., to a curious cave on his estate, about half a mile east of his hotel at Lake Point. It is, at a 

 rough guess, about 200 feet above the level of the lake, and the mouth faces the northeast. It 

 was evidently due to wave action, being situated on an ancient beach-line, while the top and 

 bottom of the cave were formed by a breccia. As my examination of it was a hasty one, no 



* The five foregoing paragraphs were written by Professor Cope. (See Amer. Naturalist, xv, 877, 1881.) 



