42 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



While Mr. Cope has proposed the genus Orconectes to include the. two blind species of cray- 

 fishes (C. pellucidus and C. liamulatm) on account of the absence of eyes, and we were inclined 

 after the discovery of a second species (hamulatus) to adopt the genus, for the reason that the 

 loss of the cornea and retinal elements, as well as the reduction in the size of the eye itself, is 

 common to two species ; yet we should hesitate to do so, from the fact that there are so many other 

 genera of Arthropods in which there are both eyed and eyeless species — the character being one of 

 great instability. At the same time due consideration should be given to the fact that such loss, 

 total or partial, of the organs of vision is of profound significance, more so than the mere syste- 

 matic zoologist is apt to recognize. Were there other good generic characters than those afforded 

 by the reduction of the eye we should retain Cope's genus Orconectes ; meanwhile it may stand as 

 a subgenus. 



ARACHNID A. 



ACARINA.* 



Rhyncholophus cavcrnarum n. sp. (PL X, figs. 1, la, \c) — This is a minute white species, .8 mm in 

 length, found near the end of White's Cave; also by Mr. Sanborn in Long Cave, 2 miles from 

 Glasgow Junction, Kentucky. 



Bryiobia f (or Penthalwus f) iceyerensis n. sp. (PI. XI, figs. 1, la, lb) — Body stouter, larger, and 

 maxillae slenderer than in the other species ; legs very long. Color, dull white. Length, l.l mm . 

 Weyer's Cave. Mr. A. D. Michael writes me that this is probably a Labidostoma Kramer, or Nicoletia. 



Lcelaps f (or Holostaspis ?) wyandotteusis u. sp. (PI. X, figs. 2, 2a, 2b) — Body thick, oval; inax- 

 illse very short, minute; maxillary palpi five-jointed, the terminal joint bearing a broad triangular 

 plate; tarsal claws long, elbowed, and spatulate. Length, 1.8 mm . Little Wyandotte Cave. 



Lcelaps (= Iphis f) cavernicola n. sp. (PI. X, fig. 3) — Body oval ; no eyes; pule horn color. 

 Length, l mm . Labyrinth, Mammoth Cave, under Oozonium auricomum on sticks. Perhaps a 

 Hypoaspis. 



Gamasus (or Hypoaspis f) troglodytes n. sp. (PI. X, figs. 4, 4a, 4tb, 4c) — Occurred in Mammoth 

 Cave with the preceding species. 



Gamasus stygius n. sp. (PI. X, figs. 5, 5a, 5b, 5c) — Of the same form as in the preceding 

 species, but the beak is nearly one-half shorter. Color, pale horn. Length, l mm . Bat Cave, 

 Carter Caves, Kentucky. 



Darnams (= Belba) bulbipedata n. sp. (PI. X, figs, 7, 7a) — Head conical; abdomen orbicular; 

 the legs long and slender, with all the joints more or less bulbous, and each bearing two or three 

 long setae. Fig. 8, Dr. Trouessart thinks, is perhaps the nymph of this species. The legs are a little 

 shorter, and the setae on the end of the abdomen much longer. End of Dixon's Cave. 



Oribata alata n. sp. (PI. XI, figs. 2, 2a) — This is a short, round species, with a stout conical 

 head, and two large wing like expansions on each side, extending in front nearly as far as the end 

 of the head ; the legs are long and slender. Collected at the end of Dixon's Cave. 



Uropoda lucifugus n. sp. (PI. X, fig. 9)— Body suborbicular, nearly as wide as long, with short 

 legs, the longest about two-thirds as wide as the body. Found in New Wyandotte Cave, attached 

 to Pseudotremia. Allied to U. Tcrameri according to Trouessart (in litt.). 



Sejus f sanborni n. sp. (PI. X, figs. 6, 6a) — Body thick, spherical, white. Length, 5 mm . 

 Maxillae and palpi very short, about one-third as long as the first pair of legs. Cave near Dismal 

 Creek, Kentucky (P. G. Sanborn). Dr. Trouessart refers this form to Sejus ? or Zercon? 



Family CHERNETID.E. 

 Obisium cavioola Pack. 



OMsium cavicola Pack., Anier. Naturalist, xviii, 202,203, with fig. February, 1884. t 

 This is certainly an aberrant species of the genus, whether we regard the size of the chelicerae 

 or the shape of the cephalothorax. The latter is much longer than broad, widest just before the 



* The descriptions of the mites are brief and imperfect, as little is known, of the genera aud species in the 

 United States, and the following notices are only preliminary. The figures, it is hoped, will enable them to be rec- 

 ognized. (See also explanation of Plates X and XI.) I am indebted to Dr. Trouessart for most of the generic names, 

 t By an oversight the author's name was omitted at the end of the article. 



