UNIVALVE MOLLUSC A. 



465 



species of Pterocera are found in the seas of both hemispheres, their 

 vulgar denomination being sea-spider or scorpion shells. A glance at 

 the illustrations (Fig. 309, Pteroceras scorpio ; Fig. 310, P. willepeda ; 

 Fig. 311, P. chiragra; and Fig. 312, P. lambis)w\\\ satisfy the reader 

 as to the general correctness of this designation. 



Fig. 311. Pteroceras chiragra 'Linnaeus). 



Fig. 312. Pteroceras lambis (Linnaeus). 



The genus Pteroceras, whose remarkable form is so well calculated 

 to excite our admiration, has yet another attraction : the colouring of 

 the shells exhibits many shades, which are particularly varied towards 

 the opening, where it is generally distinguished by great freshness 

 and brilliancy, which, added to its other characters, render it among 

 the most interesting of all the Gasteropods. 



