106 UNIVALVES. 



our coasts, though not abundantly., called Turbo 

 Clathrus, or False Wentle-trap.* It differs from 

 the true Wentle-trap principally, in having its 

 whorls contiguous. The inhabitant is one of the 

 animals that yield a purple dye : if kept some 

 days out of water it becomes sickly, and dis- 

 charges a most beautiful purple liquid. This 

 dye differs in many respects from that obtained 

 from the Buccinum Lapillus. It can be pro- 

 duced spontaneously from the mollusks ; the 

 colour when first it comes from this animal is 

 purple, and not of the same unalterable nature 

 as that obtained from the other. These shells 

 now form a separate genus called Scalaria. 



Genus HELIX f Plural, Helms. 



SNAIL. 



Generic Character. Shell univalve, spirally 

 convoluted, sub-diaphanous,f thin and fragile ; 

 aperture entire, contracted, sub-orbicular; body 

 whorl projects into the mouth, separating the 

 lips. 



* Plate IV. figure 8. t Plate V. figure 1, 2, 3. 



Diaphanous is from the Greek words 5ta, (dia) through 

 and Qaivw, (phaino) I appear. 



