76 FAUNA OP MAYFIELD'S CAVE. 



Order ISOPODA. 



Family ASELLIDAE. 



Caecidotea stygia Packard. 



PACKARD, Am. Nat., v, 1871, 751, figs. 132, 133; Rep. Peabody Acad. Sci., Salem, v, 

 1873, 95 (Mammoth Cave, Wyandotte Cave, well near Orleans, Indiana). SMITH, 

 Rep. U. S. Fish Commission 1872-73, 661 (localities as above) ; Am. Nat., vil, 

 1873, 244; Am. Journ. Sci. and Arts, IX, 1875, 477 (Caves and wells, Indiana, 

 Mammoth Cave). HUBBARD, Am. Entom., n. s., i, 1880, 37-79, fig. 10. PACKARD, 

 Mem. Nat. Acad. Sci., IV, 1888, 16, 29, pis. ill, IV (Mammoth, White's, Diamond, 

 Long, Walnut Hill Spring, and Carter caves in Kentucky; Wyandotte, May- 

 field's and Bradford caves in Indiana); Pop. Sci. Mon., xxxvi, 1890, 391, 392. 

 GARMAN, Science, XX, 1892, 240 (Upper Mississippi Valley and ^Kentucky, east 

 to Pennsylvania). STEBBING, History of Crustacea, 1893, 377. CHILTON, Trans. 

 Lin. Soc. London, vi, 1874, 252. PACKARD, Am. Nat., xxvm, 1894, 742. HAY, 

 Rep. Ind. Geol. Survey, 1896, 207 (Strong's, Eller's, Mayfield's, Marengo, Wyan- 

 dotte, Saltpeter, and Evanston's caves, and from wells and springs, all in central 

 Indiana); Proc. U. S. Nat. Mus., XXV, 1902, 225, 421, 424, 428 (Mammoth Cave). 

 RICHARDSON, Bull. U. S. Nat. Mus., 54, 1905, 434, figs. 490-492 (Graham's Spring, 

 Lexington, Virginia; Mammoth Cave; wells in Indiana and Illinois). 



Csecidotea microcephala, COPE, Am. Nat., vi, 1872, 411, 419; Rep. Ind. Geol. Survey, 

 iv, 1872, 163, 174. SMITH, Am. Nat., vil, 1872; 244 (Wyandotte Cave) . 



Asellus stygius, FORBES, Bull. 111. State Lab. Nat. Hist., I, 1876, 11 (wells, springs, 

 and drains in central Illinois). UNDERWOOD, Bull. 111. State Lab. Nat. Hist., n, 

 1886, 359. 



This eyeless and wholly bleached species is found abundantly at the 

 origin of the stream in the cave and in considerable numbers in all the 

 water of the cave. It is often found along the edge of the pools and 

 occasionally crawls upon the bank. More usually, however, it is found 

 under a stone in the water. When disturbed this isopod often retreats 

 to a flat stone, under which it conceals itself, or, this lacking, it goes to 

 shallow water or crawls out on the bank. Rarely Csecidotea stygia is 

 found outside of caves under stones or dead leaves in the water, but 

 even when quite abundant in these situations it is seldom seen away 

 from places of concealment. 



Csecidotea stygia is a weak species. It can not swim and crawls very 

 slowly. It is nearly helpless out of water, its weak legs being scarcely 

 able to push it along. While entirely blind, C. stygia is sensitive to 

 light. Its habit of living under stones and dead leaves when outside of 

 caves has already been mentioned. In caves it usually retreats from 

 bright light. It is very sensitive to a jar of the water, all individuals 

 in a pool appearing much agitated when the water is disturbed or the 

 adjoining bank sharply jarred. This species serves to some extent as 

 food for Crangonyx gracilis; attempts to keep the two in the same dish 

 in the laboratory proved disastrous to the former. The isopod is not so 

 abundant in the upper pools of the cave, where the amphipod is most 



