146 SEA-SHORE LIFE 
coast north of Cape Cod, and occurs just below low tide level on the 
Maine shore, although it is usually found in deeper water. When 
empty it is a favorite shell with hermit crabs, 
and is often dragged long distances from its 
true habitat. 
The Oyster-Drill, (Urosalpinx cinerea, 
Fig. 105), isa destructive little snail, common 
in shallow water on stony bottoms down to 
Fig. 105; OYSTER DRILL. about sixty feet in depth; and while it ranges 
De Sa a from Florida to Nova Scotia, it is rare and 
local north of Cape Cod. 
It is most abundant in Chesapeake Bay and Long Island Sound. 
The shell is less than one inch long, and the lip is extended out in 
a projecting snout that serves to protect the siphon of the animal. 
It is dull brownish-gray, and there are numerous rough, raised, 
whorls and longitudinal ridges over the shell. The egg cocoons are 
laid during summer on the under surface of dead shells or stones, 
and are spindle-shaped, resembling little yellow vases made out of 
parchment. The stems of these little vases are very short, and angu- 
lar ridges extend along their sides. 
This snail is one of the worst enemies of small oysters and other 
bivalves. It rasps a small round hole through the shell by means of 
the sharp, horny teeth of its tongue, aided 
possibly by the secretion of sulphuric acid. 
Then having penetrated the shell it sucks the 
contents out at leisure. Next to the starfish 
there is probably no worse enemy of the oys- 
ter than this snail, and its popular name of 
oyster-drill is well earned. It attacks its vic- 
tims throughout the year, but fortunately it «i 
is unable to drill through the shells of full 9 2 
grown clams and oysters. 
Large numbers of little clam shells that 
have been drilled by this pest are always to iy. 166 Above WARE 
be seen cast up upon our beaches. TRIVITTATA. 
The Mud-Flat Snail, (Nassa obsoleta, coh ieeene aes 
Fig. 106), is a small snail ranging from 
Tampa, Florida, to Nova Scotia. It is rare north of Cape Cod, but is 
most abundant on the mud flats of Long Island Sound, which it 



literally covers over wide areas. 
