SHELLS WITHOUT CANALS 



211 



mistake. An examination of the inside of the shell 

 will quickl}^ put to rest any doubt about the identity 

 of the species, however, tor the Chama has a hinge- 

 tooth, while the Hoof-shell plainly shows the horse- 

 shoe shaped muscle-scar. Some consider this species 

 as only a variety of the last. 



Amalthea tuniens^ Cpr., the Sculptured Hoof- 

 shell, {Hipponyx tiunens)^ has a much more regular 

 shell than either of the others. The apex is recurved, 

 and the lower part of the shell is somewhat bearded. 

 Radial lines run from the apex to the edge, and they 

 are crossed by lines of growth. Some specimens 

 greatly resemble a short "horn of plenty." The shells 

 are white in color, while the beard, if present, is 

 light brown. The shells are seldom over half an 

 inch in length. 



Figure 204 represents a 

 large shell named Polynices 

 lewisii^ Gld., L e w i s's 

 Moon-shell. It is a mem- 

 ber of the Natica family, 

 all the members of which 

 are distinguished for their 

 ferocious nature, so that 

 they might well be called 

 snails of prey. 



Plowing along through ^. ^^, 



00 & Fig. 204 



the wet sand by means of 



its enormous foot, it no sooner reaches an unfortu- 

 nate clam than the flint drill which it carries in its 

 mouth is stretched out rmd begins to accomplish its 

 work of destruction. The helpless clam has no means 



