344 



pears to have favoured the latter opinion ; from whence 

 he concludes, it muft belong to the water, as the animals 

 of all land (hells poffefs four tcntacula: and he appears 

 the more confirmed in that opinion, on account of its 

 being furnifhed with a ftrong teftaceous operculum. 



It is indeed the only inftance we can produce, of a land 

 fliell being provided with a permanent teftaceous oper- 

 culum ; but the animal of Turbo Carychium, as well as 

 this, has but two tcntacula : and Muller informs us his 

 Vertigo pu fill a, our Turbo Vertigo, which is alfo a land 

 fhell, is inhabited by a Umax of a more fingular forma- 

 tion; for v.'ith only two tcntacula, the eyes are placed at 

 their tips : fo that, although we have not hitherto dif- 

 covered any aquatic Umax with four regular tcntacula,'^ 

 yet fuch animal pofTefTrngonly two, is not a criterion of 

 its being; an inhabitant of the water. 



't> 



The animal of this fliell has alfo another uncommon 

 property for a land Umax, as we are informed by Lis- 

 ter, who fays they are of different fexes. Whether 

 this is the cafe in the few other land fpecies with two ten- 

 tacula remains to h-e. proved ; it is however probable, 

 and that thofe with four tcntacula are invariably her- 

 maphrodite, and have their fuperior ones ocellated. 



Lister has furtlier elucidated the fubjeft, by giving 



a 



* The phimofe appendage on the back of the head of Turho fonlinalh and 

 Helix a'ljlata, cannot be confidcrcd as proper tentacula. 



