TESTACELLUS. C0Lt3IACEA. 6^ 



a kind of thread, formed of the viscid substance 

 that covers the body. 



" Testacelliis is a very interesting genus, lately 

 found in England : the animal has a resemblance 

 to the common slug : it carries the shield on the 

 hinder part of the body. 



'' Testacellufi scutellimi feeds on earth-worms, 

 and can so much lengthen the body that it follows 

 them under-ground. 



" Our next order will show great alterations in 

 the very large genus Helix. I shall name to 

 you those of Lamarck. 



" The third order o£ Mollusca, Trachelipoda, 

 begins with a well-known genus, the snail. Helix. 

 The term signifies that the^oo^ is situated under 

 the neck, or anterior part of the body. The fa- 

 milies in this order are numerous : they are di- 

 vided into two sections ; the first includes those 

 that breathe only in the air ; the second those 

 that can exist only in the water, and are furnished 

 with a syphon. 



a 



First section : family CoUmacea ; genera 

 numerous ; animals live upon land only ; ten- 

 tacula generally four ; during winter they enclose 

 themselves in their shells, with a false operculum. 



Helix, snail Helix. 



Carocolla Helix. 



Anostoma Helix. 



