66 ONCHIDIUM. LIMAX. 



" Our next family, the Limacina, has 

 Onchidium, 

 Parmacella. 

 Limax, slug. 

 Testacella, 

 Vitrina. 



" Oncliidium is a genus from the shores of 

 the Indian seas. The animals have a shield : 

 they live near the sea, and some are known to 

 swim, often coming to the surface to breathe 

 the air. 



" Parmacella was found by an English tra- 

 veller in Mesopotamia. It has a shell covered by 

 a shield. But you have not answered my ques- 

 tion respecting the Limax, or slug." 



" I do not recollect,"" replied Charles ; *' yet 

 how often we see slugs !" 



*' If I may be allowed to answer,'' said Lucy, 

 *' I think that the slug has what I now under- 

 stand to be a shield. I have often watched the 

 animal contract itself, and seen a broad, flat piece 

 upon the back, which I thought was a kind of 

 shelter for it." 



" The Limax, or slug," continued Mr. Elliot, 

 " is, in fact, provided with a coriaceous escut- 

 cheon, or shield, beneath which the animal partly 

 conceals itself. The Limax agrestls, or spin- 

 ning-slug, has the power of suspending itself by 



