SHE EES  WittOouth CANALS 227 
recurved, and the lower part of the shell is some- 
what bearded. Radial lines run from the apex to 
the edge, and are crossed by lines of growth. Some 
specimens greatly resemble a short ‘‘horn of 
plenty.’’ These shells are seldom over half an 
inch in length. 
Figure 247 represents 
a large shell named 
Polynices (Lunatia) 
lewisu, Gld., Lewis’s 
Moon-shell. It is a 
member of the Natica 
family, all the members 
of which are distin- 
guished for their fero- 
cious nature, and which 
might well be called 
snails of prey. 
Plowing along through the wet sand by means 
of its enormous foot, it no sooner reaches an unfor- 
tunate clam than the flint drill which it carries in 
its mouth is stretched out, and begins to accom- 
plish its work of destruction. The helpless clam 
has no means of flight from such an enemy; and 
if its hard shell is not a sufficient protection, it 
is in a sad case indeed. And in truth, the case is 
sad, for the limestone shell is no match for the 
silica drill, and when once it has reached the sav- 
ory meat inside, the robber makes short work of 
his victim. A high-handed proceeding, no doubt; 
but then, it contrasts rather favorably with our 
way of opening clams and oysters. 
Fig. 247 
