24 MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 



this peculiar troglodyte assemblage, need uot demand the "numberless generations" insisted on by 

 Mr. Darwin in his Origin of Species. The time since the present climatic relations and the present 

 fauna came into existence may, it seems to us, be estimated by a few thousands rather thau by 

 hundreds of thousands of years. 



It should be borne in mind that early in the River Terrace epoch, when the cavernous region 

 was flooded, no life could have existed in these caves. Even now that extensive cavern, Howe's 

 Cave, excavated from the Silurian limestone in Schoharie county, New York, is said to have no 

 life in it except a few common crickets (CeuthopMlus maculatus), found everywhere in New York 

 and New England under stones and logs. In his excellent account of Howe's Cave, through 

 which a stream runs, Eev. Mr. Hovey remarks : 



Bat the guide assured me that during a rainy season * * * there were times when the whole cavern would 

 be filled and, as he said, " pour forth a mighty flood." 



Again, on page 195, he says: 



The swiftness of the cave stream and its liability to sudden overflow have prevented the aborigines from making 

 this cavern a place either of residence or sepulture. It may be doubted, indeed, if they knew of its existence. Few 

 animal remains have been found here. Large numbers of bats, however, hibernate in its chambers, clinging in 

 clusters, like swarms of bees. No fish inhabit the lake or the stream, except such as have been put there by the hand 

 of man, and even these forsake these subterranean waters when the spring freshets give them the opportunity to do so. 



It is- noteworthy that in glaciated regions the few caves in existence, of which. Howe's Cave is 

 the largest kuown to us, do not support a true cave fauna. In Europe the Carniolan and Pyreuean 

 region may have been glaciated, but we infer not. In the United States, at all events, the cavernous 

 regions of southern Indiana, Kentucky, Tennessee, and Virginia lie south of the great moraine. 

 It is plain enough that the caves of Carniola and other portions of Austria and of Illyria, as well 

 as the caves of Basse-Pyrenees in France and the caves of Spain, have been colonized from members 

 of the existing fauna, which was derived mainly from the shores of the Mediterranean, aud are 

 warm, temperate in their complexion, belonging to the Mediterranean sub region. 



THE SOURCE OF THE FOOD SUPPLY OF CAVE ANIMALS. 



So far as observed cave animals, even the carnivorous species, take remarkably little food, and 

 the source of the food supply in caverns is naturally a question of much interest. As regards tbe 

 voracity of the blind-fish (Amblyopsis spelceus), several of which I had the pleasure of seeing in 

 Dr. John Sloan's aquarium, he wrote me as follows, under date of May 9, 1875 : 



I have some large blind-fishes which I put in my aquarium in August, 1873. They have taken no food, except 

 what has grown up in the water and on the sand in their tank. Are they nourished by the confervoid and animalcule 

 growth ? 



This quotation will also give proofs that this blind-fish may be readily kept for over a year in 

 a large aquarium, the one in question having stood in a well-lighted room in Dr. Sloan's house. 



It is, however, known that an Amblyopsis, in one case at least, swallowed a fish with eyes, as 

 Dr. Wyman found in 1856, in the stomach of an Amblyopsis he was dissecting, a small fish figured 

 by Professor Putnam (Amer. Naturalist, Jan. 1872, PI. I, fig. 13). 



Without much doubt the natural food of the blind-fish, besides an occasional young fish of 

 its own or some other species, is the .blind crayfish, as well as Crangouyx, and perhaps the Cseci- 

 dotaea, though the latter usually lives concealed under stones. 



The food of the blind crayfish appears to consist of living Caecidotsea. Mr. Moses N. Elrod, of 

 Orleans, Orange county, Indiana, writes me as follows regarding this point under date of June 4, 

 1873 : 



Since writing the above I have collected over a hundred CsBcidotsea and a number of other forms (Crangonyx) 

 from a well in town. They were in and on the bucket, that had been in the bottom of the well for several days. I also 

 have a live eyeless crayfish taken from one of our own wells yesterday, and have fed the Cscidota^a to it. If the 

 Ctecidotsea are put near, in its claw, it eats them almost instantly. I am trying the blind-fish to see if they will eat 

 them. I have three live blind-fish in my cellar, one as large as they ever grow, and I think it a female. 



The blind crayfish, then, appears to prefer living small Crustacea, and is not omnivorous in its 

 appetite. Regarding this point Mr. Putnam remarks as follows : 



Many of the specimens [of 0. pellucidus] were brought alive to Massachusetts, and several still continue in good 

 condition, though they have eaten very little since their capture. I have several times offered them food in the shape 



