40 



CLASS MOLLUSCA. 



The Caniculated Pear-Shell, (Py?'M?a caniculata.) 



This shell is found in the Icy Sea, and on the coast of 

 Canada, and attains the length of seven inches. The 

 animal of the Pyrula is at present unknown! There is 

 a kind of keel or ridge along the edge of the whorls, 

 which is obliterated in very old specimens. There are 

 as many as eight-and-twenty species of this shell. 



The Babylonian Split-Mouth, 

 (Plewrotoma babylonia.) 



The Bab} Ionian Split-Mouth is found in the East Indies 

 and the Molucca Islands, and is about three inches and 



Tiirho marmoratus. Pleurotoma hahyloiiia. Trochus imperialis. 



a quarter in length. It is said that the animal of this 

 shell, when in motion, has its foot separated as it were 

 from its body by a long thick footstalk, which arises 

 from the centre of the mantle, which is at this time 

 turned back over the shell. This separation of the foot 

 has the effect of causing the creature to tumble over 

 frequently, from the great weight it has to support. 



