42 
MEMOIRS OE THE RATIONAL ACADEMY OF SCIENCES. 
While Mr. Cope lias proposed the genus Orconectes to include the two blind species of cray¬ 
fishes (C. pellucidus and 0. ho//ivlulus) 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. 
ARACHNIDA. 
Acarina * 
Rhyncholophus cavernarum n. sp. (PL X, figs. 1, la, le)—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 ? (or Penthalwus f) weyerensis n. sp. (PI. XI, figs. 1, la, 1&)—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. 
Loelaps ? (or Holosiaspis ?) wyandottensis u. sp. (PI. X, figs. 2, 2a, 2b)— Body thick, oval; max¬ 
illae very short, minute; maxillary palpi five jointed, the terminal joint bearing a broad triangular 
plate; tarsal claws long, elbowed, and spatulate. Length, 1.8““ Little Wyandotte Cave. 
Loelaps (= Ipliis?) cavernicola n. sp. (PI. X, fig. 3)-Body oval; no eyes; pale 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, lb, 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. 
Damceus (= Delba) bulbipedata n. sp. (PI. X, figs. 7, la) —Head conical; abdomen orbicular; 
the legs long and slender, with all the joints more or less bulbous, and each bearing two or three 
long setm. 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. lcrameri according to Trouessart (in lift.). 
Sejus ? sanborni n. sp. (PI. X, figs. 6, 6a)—Body thick, spherical, white. Length, 5““. 
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 f or Zercon 
Family CHERNETIDiE. 
Obisium cavioola Pack. 
0bisium eavicola Pack., Amer. Naturalist, xviii, 202,203, with tig. February, 1884. t 
This is certainly an aberrant species of the genus, whether we regard the size of the chelicerte 
or the shape of the cepbalothorax. 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 and 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. 
