78 FAUNA OF MAYFIELD'S CAVE. 



family from a cave in Missouri. Acanthoniscus cacahuamilpensis(Ei\mek) 

 occurs in Cacahuamilpa Grotto in Mexico (Packard, 1894, 732). A closely 

 related family contains Haplopthalmus puteus Hay (1899, 871) from a 

 well at Irvington, Indiana, and Brackenridgia cavernarum Ulrich 

 (1902, 91), both of which are white, the former having small eyes and 

 the latter none. Another relative of Porcellio is Euphiloscia elrodii 

 from a cave at Orleans, Indiana (Packard, 1873, 97) . Several eyeless 

 and light-colored relatives of Porcellio are found in European caves. 

 One of these, Titanethes albus Schiodte, is abundant and generally 

 distributed in caves in Carniola and Istria, in Southern Austria. 



Among other subterranean isopods are Ciralonides texensis Benedict 

 (1895) from an artesian well at San Marcos, Texas, Conilera stygia 

 Packard (1900) from a well at Monterey, Mexico, Phreatoicus assimilis 

 Chilton, Cruregens fontanus Chilton, and Phreatoicus typicus Chilton 

 from wells in New Zealand (Chilton, 1894, 185-218). All these species 

 are described as eyeless and white or "transparent." 



Order AMPHIPODA. 



Family GAMMARIDAE. 



Crangonyx gracilis Smith. 



SMITH, Am. Journ. Sci., ser. 3, II, 1871, 452 (Lake Superior) ; Rep. U. S. Fish Com- 

 mission 1872-73, 654. FORBES, Bull. 111. St. Lab. Nat. Hist. No. 1, 1876, 6 (Illinois)- 

 HAY, Am. Nat., xvi, 1882,241 (ponds and streams, Irvington, Indiana). PACKARD, 

 Mem. Nat. Acad. Sci., IV, 1888, 16, 36 (Lake Superior, Michigan, Mayfield's Cave). 

 HAY, Proc. Ind. Acad. Sci,, 1891, 150. BLATCHLEY & HAY, Rep. Ind. Geol. Survey, 

 1896, 206 (Eller's, Donnehue's, and Mayfield's caves). 



This species is quite abundant in the water of the cave. The blind 

 fishes feed upon it, and hence its distribution is limited. It is rarely 

 found about the lower pools of the cave, where the fishes are most 

 abundant. In the upper pools, where there are no fishes, it is very 

 common. It does not occur in shallow water to any extent; hence is 

 not found in the shallow parts of the stream, where Csecidotea stygia is 

 so numerous. 



Ordinarily this animal is to be observed quietly resting or crawling 

 about over the bottom of the pools. When disturbed it swims by rapid, 

 jerky movements and often rises toward the surface, especially when 

 persistently pursued. It may be driven to the very edge of the pool, 

 when it often crawls partly out of the water. It is quite sensitive to a 

 disturbance of the water, or to light, which it avoids. 



This species sometimes feeds upon the cave isopod Csecidotea stygia. 

 I have twice seen it in an aquarium catch a living Csecidotea. In con- 

 finement it keeps under cover or along the dark edges of the aquarium 

 much of the time. It feeds upon any organic matter or even upon the 

 carcass of a fellow. I was sometimes suspicious that the larger ones 



