296 HELICIDJE. 



guished the French shell from it under the name of 

 Liesvillei. Whatever difference of opinion may, however, 

 exist as to the scientific value of the species whicli this 

 last-named author has so prodigally described, his biblio- 

 graphical learning and laborious research cannot fail to 

 command our admiration. The two generic names of 

 Cacilioides and Cacilianella are founded on a peculiarity 

 which does not appear to be shared by any other British 

 land or freshwater snail ; although in the famous caves 

 of Adelsberg many of such instances occur. It is, that 

 this snail is eyeless. This remarkable fact, with respect 

 to the Achatina acicula (which will be presently de- 

 scribed), was first noticed by Nilsson, and it has been 

 fully confirmed by subsequent observation. The A. aci- 

 cula always lives underground ; and the conditions of its 

 habitat are therefore similar to those of the several spe- 

 cies of Zospeum, living in the inmost recesses of the 

 Illyrian caverns, into which the light of day never pene- 

 trates. It is true that Testacella, which is also a sub- 

 terranean mollusk, is not deficient in those organs which 

 are called eyes ; but this animal passes some of its 

 time (especially in the pairing-season) above ground, 

 while our little Achatina has never been observed on* 

 the surface in a living state. Similar exceptions of eye- 

 less species, belonging to genera the animals of which 

 are usually ocellated, occur (although very rarely) among 

 our marine Cephalic Mollusca — as, for instance, Eulhna 

 stenostoma and Mangelia nivalis', but these are deep- 

 water species, and very little is known as to the extent 

 to which light penetrates into the abysses of the ocean, 

 or as to its action on the sensorial organs of inverte- 

 brate animals. In all probability the A. acicula lives 

 upon animal matter ; for, in the spots where it has been 

 found living, no underground fungus or other vegetation 



