24 FAUNA OF MAYFIELD'S CAVE. 



This species has been more widely studied than any other cave animal, 

 perhaps, and certainly more than any other American cave animal. 

 Its habits, anatomy, food, origin, etc., are discussed in the articles listed 

 above. Its natural distribution includes the subterranean streams in 

 the Mississippi Valley east of the Mississippi River and south of the 

 East Fork of White River. It was introduced into Mayfield's Cave in 

 the summer of 1901 by Dr. Eigenmann and is now abundant, breeding 

 freely. 



Fishes of all sizes are abundant in favorable pools where the water 

 reaches 6 inches or more in depth, but are most abundant in those pools 

 where there are shelving rocks beneath the surface or where the pools 

 extend under the edge of the wall. They swim slowly, often near the 

 surface, and pay little attention to light or sound. But if the water is 

 considerably disturbed they swim quickly downward and soon find their 

 way under a shelf of rock or into some other retreat, from which they 

 do not emerge for some time and then very slowly and cautiously. It 

 is very significant that during the unusually high water noted in April, 

 1904, when the cave was almost full of water which washed great 

 trenches at places, the fishes were not washed out of the cave. After- 

 wards they were apparently as abundant as before. For a fish as 

 sluggish as the blind fish it would seem to have involved quite a struggle 

 to resist the force of the current. 



The young are so nearly transparent that they can scarcely be 

 detected, except by the shadows their almost colorless but opaque bodies 

 make on the bottom. Young, 8 mm. long, were seen in the shallow 

 water of one of the larger pools in November, 1905. There seemed to 

 have been young from at least two females, for a few days later young 

 of two sizes were seen. 



In the adult Amblyopsis the eye can scarcely be located and the 

 alimentary canal bends forward so that the anus is below and between 

 the gill slits; while in young 8 mm. long there are conspicuous black 

 eyes, and the anus is between the ventral and the anal fins, as is usual 

 among fishes. By March 1 the young were 18 mm. long and had much 

 of the white color characteristic of the adult. The eyes were less con- 

 spicuous, but the anus was still behind the ventral fins. I was not able 

 to keep this series longer. Eigenmann (1900c, 119) finds that "in an 

 individual 35 mm. long the anus is situated between the origin of the 

 pectorals; in one 25 mm. long it lies between the pectorals and ventrals; 

 in the young it lies behind the ventrals." 



An Amblyopsis 56 mm. long was examined to determine the food of 

 this species in Mayfield's Cave. The fish had been cut open and placed 

 in strong alcohol when caught. The stomach contents consisted of a 



