NATICA. 175 



becoming immersed in it, so that her infant progeny may 

 not be prematurely choked. 



Another very curious character in this genus is the ap- 

 parent large size of the animal compared with its shell. To 

 see a Natica when in action, one would suppose it much 

 more likely that the soft parts were meant to wrap up the 

 shell and keep it polished, than that the shell should ever 

 afford shelter and protection to the whole animal. Yet the 

 fact is, that all that mass of fleshy substance, and all that 

 broad expanse of mantle and foot, can not only be neatly 

 folded and gathered within the hollow' of its shelly covering, 

 but can be firmly and safely enclosed by the hard semicir- 

 cular door carried on the foot. 



As the British species exhibit much the same peculiarities 

 as those of foreign coasts, I shall avail myself of the obser- 

 vations of Mr. Arthur Adams, who enjoyed so many oppor- 

 tunities of seeing, and describes with such felicity what he 

 saw, of the habits of mollusca among the islands of the East. 

 ^' N. melanostoma" that gentleman observes, "is furnished 

 with a strong coriaceous foot, well developed in front, by 

 means of which it perforates the sand, while its tentacles are 

 protected; but when the tide rises and covers the sands, 

 the large side-lobes and dilated hind part of the foot are 



