106 UNIVALVES. 



European and American Seas, and is found upon 

 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 produced 

 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 HELIXf Plural, Helices. 



Generic Character. Shell univalve, spirally 

 convoluted, sub-diaphanous, J thin and fragile ; 

 aperture entire, contracted, sub-orbicular; body 

 whorl projects into the mouth, separating the 

 lips. 



* Plate IV. figure 8. f Plate V. figures 1, 2, 3. 



J Diaphanous is from the Greek words Sta, (dia) through, 

 and (paivw, (phaino) I appear. 



