ELIND FAUNA OF CAVERNS. 77 



Very recently, however, investigations in various parts 

 of the world have revealed the curious circumstance of 

 somewhat extensive series of animals inhabiting vast 

 and gloomy caves and deep wells, and perfectly deprived 

 even of the vestiges of eyes. Enormous caves in North 

 America, some of which are ten miles in length, and 

 other vast and ramified grottoes in Central Europe, have 

 yielded the chief of these ; but even in this country we 

 possess at least four species of minute shrimps,* three 

 of which are absolutely blind, and the fourth (though it 

 has a yellow speck in the place of an eye) j^robably so. 

 All these have been obtained from pumps and wells in 

 the southern counties of England, at a depth of thirty or 

 forty feet from the surface of the earth. 



The crustacean Calocaris, already mentioned as in- 

 habiting the amazing depth of one hundred and eighty 

 fathoms, appears to be blind, for though eyes are present, 

 their surface is perfectly smooth and destitute of facetted 

 cornege, and white, shewing the absence of colouring pig- 

 ment. Vision can scarcely exist with such a structure, 

 and this is in keeping with the habits of the animal ; for 

 not only would the vast superincumbent body of water 

 absorb all the rays of light, and make its sphere of being 

 totally dark, but, in addition to this, it is of fossorial 

 habits, burrowing into the sandy mud at the bottom.-|- 



The Mammoth Cave in Kentucky consists of iunumer- 



* Belonging to the genera NijjJiargus and CraiKjonyx. (See Nat. Hist. 

 Jievieio, 1859 ; Fr. Soc, p. 164). 

 t Bell's Brit. Crust., p. 236. 



