DISCREPANCIES. 



try 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) probably 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 

 inhabiting 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 corneae, and white, 

 shewing the absence of colouring pigment. 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. t 



The Mammoth Cave in Kentucky consists of in- 

 numerable subterranean galleries in the limestone 

 formation, some of which are of great extent. 

 The temperature is constant throughout the year 

 — .V.) deg. Fahr. A darkness, unrelieved by the 

 least glimmer of light, prevails. Animals of vari- 

 ous races inhabit these caves, all completely blind ; 

 for though some have rudimentary eyes, they 

 appear useless for purposes of vision. Among 

 these are two kinds of bats, two rats, (one found 

 at a distance of seven miles from the entrance,) 

 moles, fishes, spiders, beetles, Crustacea, and sev- 

 eral kinds of infusoria.:}: 



* Belonging to the genera Niphargus and Crangonyx. (See 

 Nat. Hist. Review, 1859; Pr. Soc., p. 164.) 

 + Bell's M Brit. Crust.," p. 236. 

 % Trans. Roy. Soc. Edinb., Dec, 1853. 

 79 



