The Moon Shells and Velvet Shells 



the burrowing, gliding organ of locomotion. In shape it is some- 

 what like the bottom of an old-fashioned flatiron; the broad, 

 truncated end is forward. A fleshy band on top of the foot 

 folds back over the head, protecting it as the burrowing foot 

 drags the body rapidly after it through the wet sand. The eyes 

 are wanting or buried under a thick epidermis. 



This blind, mole-like mollusk fmds plenty to eat in the zone 

 just under the surface of the sand. Clams and other shell fish 

 are there. Down comes the hood from over the head when a 

 victim is met. The long proboscis is set, and the radula it con- 

 tains soon has a neat round hole drilled in the shell, through 

 which the soft parts are extracted by the sucking mouth of the 

 bloodthirsty Natica. 



The largest holes drilled in various bivalve shells are usually 

 charged to the Naticas, although the evidence is partly circum- 

 stantial. The activity of the mollusk argues a keen appetite, 

 and its predatory reputation is quite lived up to if a single speci- 

 men is put into an aquarium with clams and a variety of other 

 mollusks of less strenuous habits. Well may Natica be bold, 

 for at the least warning of danger it draws in the foot, and the 

 horny operculum locks the door tight. 



The eggs are laid in a sticky mass of clear jelly which is 

 moulded over the shell; this explains its peculiar collar shape. 

 There is but one layer of egg cases, arranged in regular quincunx 

 order. A layer of fine sand covers each side of the collar, making 

 it about the thickness of an orange peel. While this remains in 

 the water the mucus is rubber-like, and the eggs are safely con- 

 cealed under the protective film of gray sand. Cast ashore the 

 sand collar becomes dry and brittle. Who has not seen these 

 collars, six inches in diameter and open at one side, lying on the 

 beach? It is useless to try to carry one home without having it 

 shattered. Near hatching time the sand falls off, and the eggs 

 b2Come visible. 



N. heros ranges along shore in sand or mud, devouring, besides 

 living bivalves, dead fish and other victims of accident. On 

 New Jersey beaches the surf clam (Madra solidissima) seems to be 

 the prey it prefers. Its method is to clasp the victim in its 

 voluminous foot while the drill attacks the shell near the hinge. 

 Diameter, 3 to 4^ inches. 



Habitat. — Maine to New Jersey. 



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