NATURAI. HISTORY OR AMERICAN LOBSTER. 
185 
some cases the burrows were under rocks, and the entrance was often much larger than 
that described, possibly owing to the union of the mouths of two originally distinct 
burrows. The pile of dirt and the broken clam shells which are sometimes seen near 
the hole of the lobster recall the excavations of the muskrat. It was exceptional to 
see a lobster with his tail projecting from the burrow, and when disturbed in this posi- 
tion they were quick in disappearing. 
In digging, lobsters probably make use of their large claws and walking legs, and 
possibly the tail fan may be brought into service as a scoop or shovel, but we have no 
observation in support of the latter supposition. Yet, in some cases we have noticed 
the underside of the tail fan to be scratched and scarified, and the marginal fringe of 
hairs worn down in a way to suggest the probability of such use. 
Mead {193) found that the young lobster sometimes burrows in its fourth or 
lobsterling stage, and this instinct is very pronounced in all its later phases. It removes 
bits of gravel presumably with its claws and deposits them short distances away, thus 
digging to a depth of 2 or 3 inches. Young lobsters, like the old ones, hide in their 
holes, and issue stealthily in search of prey. Indeed, it may be said that such com- 
manding instincts of the adult as preying, concealment, and fear, are manifested sud- 
denly and for the first time in the fourth stage. 
The burrowing habits of certain species of crayfish are well known, while those 
of the stomatopods (see chap, i) are equally characteristic. We meet with the 
same habit in many snapping shrimps, expressed in a greater or less degree in terrestrial 
crabs, and in a great number of the lower Crustacea. 
FOOD AND PREYING HABITS. 
The food of the adult lobster consists principally of fish, alive or dead, and of 
invertebrates which inhabit the bottom and come within its reach. It is not unusual 
to find bits of algae or common eel grass in its stomach, and at times in such quantities 
as to suggest that it may not be an accidental occurrence. Vegetable matter, however, 
forms at most but a small and casual part of its diet. Fragments of dead shells, coarse 
sand, and gravel stones as large as duck shot are also swallowed. The former yield 
lime, which is in some measure absorbed; the latter are not needed in grinding the food 
as in the gizzard of the domestic fowl, since the lobster’s stomach has, as is well known, 
a mill admirably adapted for this purpose, and their occurrence is probably accidental. 
I have dissected soft lobsters, with fragile papery shells, from to inches long, 
in which the stomach was literally crammed with water-worn calcareous fragments 
of the dead shells of crustaceans and mollusks such as one can gather on the beach, 
besides other shells of mollusks which had undoubtedly been eaten alive. This sug- 
gested the possibility that the supply of lime for hardening the new shell might at 
times be obtained in this way (see 149; p. 89-90) for it seemed hardly probable that 
they would be swallowed to be immediately regurgitated. The lobster undoubtedly 
regurgitates the insoluble and indigestible parts of its food, as is the known habit of 
crayfish. Some such outlet for waste matter is absolutely necessary in an animal 
