CAVE ENVIRONMENT. 199 



avoiding it. Cattle come down to drink in this cave within the shaft of light. The 

 indirect result of this is a great abundance of blind-fish food. In the movements 

 and distribution of the fishes in this cave we have a clear balance struck between 

 the positive attraction to the food and the negative response to the light. 



The same reactions demonstrating perception and tropic relations to light 

 are seen in the Donkey Cave near by. In this cave I have never seen a blind 

 fish within the shaft of light, but have seen and caught them in numbers in the 

 expanse of shallow water in the shadow and total darkness to the left of the shaft 

 of light. While fishing in Ashton in December, 1903, I caught 3 specimens in the 

 lighted part of the cave and about a dozen in the dark recesses to the right of the 

 entrance. 



Unfortunately, on account of the difficulty of getting about over the jagged 

 country, I have been able to visit but few caves at night, but the observations in 

 the Carboneria well were exceedingly instructive. 



A few bushes growing over the well shade it to a certain degree. As stated 

 elsewhere, poles and fence rails were placed slanting into the water crossing each 

 other and in sufficient number to form a teetering foothold that enabled me to stand 

 waist deep in water. From this position every part of the well was within reach of 

 my net, except pockets in the sides too small for the net and the indefinitely extend- 

 ing side rifts I have mentioned. 



On visiting the well about 9 a. m. perhaps as many as 10 stygicolas were seen 

 swimming about or resting on the wood or sides of the well. I entered the well 

 but succeeded in catching only one fish ; the others readily escaped either by making 

 for the dark side rifts or by hugging the walls of the well and entering the small 

 pockets where I could not get them. There seemed to be no hesitation in their 

 actions. I again entered this well the same night. Liberally discounting the 

 result for the experience already gained in entering the well and knowledge of the 

 location, the result alone is evidence of a distinct difference in the actions of 

 the fishes at night and in the day — I caught twelve. 



Their actions were quite different. While in the daytime they seemed able to 

 locate the dark recesses and make for them with precision, their action at night 

 gave distinct evidence of confusion and lack of ability to readily escape. They 

 could be easily followed with the pencil of light from the lamp and picked up with 

 the net. 



TEMPERATURE. 



The fluctuations in the air temperature of caves with small openings are, in a 

 climate like that of Indiana, reduced to a few degrees Fahrenheit, and must be re- 

 duced to a minimum in a climate like that of Cuba. The temperature of the water 

 will also fluctuate but little. The air of caves that are open like that of Ashton 

 will, on the contrary, fluctuate to nearly the same extent as that of the epigean 

 neighborhood. -The nights of the Cuban winter are cool and the temperature of 

 the water in the open pools of these caves may be reduced a few degrees. No direct 

 observations are at hand on this point. 



The temperature of the water in 18 caves containing fishes, taken in June, 1905, 

 showed a total range from 74 to 76.5 Fahrenheit. Only 2 caves had a temperature 

 as low as 74 ; 3 of 75 ; 5 over 75.5 ; 6 of 76 ; 2 of 76.5 . 



