LIMAX. 



27 



M. Moquin-Tandon characterizes the species as having the con- 

 centric strise of the shield disposed into two separate masses, a mass 

 on each half of the shield, and remarks that De Ferussac's L. alpinus 

 differs from it in having the concentric strise in one mass only, like 

 the other striated-shield Limaces. I have not been able to detect 

 this difference, nor is it noticed by any other writer. He gives 

 sixteen varieties occurring in France, and they are Little less numer- 

 ous in Britain. The animal is rather sluggish in its movements, and 

 when irritated dilates its shield, and secretes abundantly a whitish 

 mucus. 



Genus IV. TESTACELLA, Cuvier. 



Animal; body semi-cylindrical, swollen posteriorly, tapering and 

 susceptible of elongation towards the head, integuments wrin- 

 kled or Linearly veined ; head with two pairs of tentacles, the 

 upper pair much the longer with eyes just below the extre- 

 mities, tentacles rather approximating at the base, then diver- 

 gent ; shield combining with the general integuments ; pulmo- 

 nary sac at the posterior end of the body, covered by a lobed 

 slightly extensile mantle, which secretes an external shell, 

 beneath the right side of which is the respiratory orifice. 



Shell ; ear-shaped, with a subspiral umbonal nucleus, covered by a 

 thin horny epidermis. 



