LIFE HISTORY OF THE BLUE CRAB. 5 
An injured crab, if thrown into the water, will be speedily set upon by its associates and torn to 
pieces. Even one that is uninjured, if small or in the soft-shelled condition, is likely to be captured 
and eaten by stronger individuals. 
In eating a bit of food the crab first grasps it in the large claws and pushes it back under the front 
of the shell, where it is seized between the tips of the second pair of legs and pushed forward and upward 
to a point where it can pass between the third maxillipeds to the jaws. These strong organs masticate 
the food, while the other mouth parts prevent the escape of the smaller particles. It is then swallowed 
and the complicated set of teeth in the stomach reduce it toa thin fluid mass before it is allowed to 
pass into the intestine. 
REPRODUCTION. 
MATING. 
Among the crabs of Chesapeake Bay, mating occurs chiefly in Maryland waters 
and lasts from about the middle of July to the last of August, although mating crabs 
are seen earlier than this in the lower part of the Bay. The crab reproduces by means of 
eggs which are laid by the female and carried on the abdomen until hatched, as described 
on page 97. Previous to being laid the eggs are fertilized by spermatozoa which have 
been implanted in the body of the female crab by the male at the time of copulation. 
Mating and copulation occur, as far as is known, once only in the lifetime of the female 
crab. This takes place when she is yet soft at the time of the last molting, when the 
triangular-shaped abdomen changes to the rounded form. For a few days previous to 
copulation the female is carried about by the male, which clasps her, back uppermost, 
against the lower side of his body by means of his three pairs of walking legs. This 
leaves his claws and swimming legs free and he is enabled to feed or swim about. He 
at times frees a number of walking legs and moves over the bottom. Such pairs of 
mating crabs are called ‘‘doublers’’ and are often seen clinging to posts or pilings in 
the water. As already noted, the male’s hold upon the female is quite tenacious, and 
both individuals are caught in great numbers on the trot-line, due to the male seizing 
the bait and both being drawn to the surface. 
In all the numbers of pairs which have been observed by the author and by crabbers 
who were questioned, no male crab has ever been found, in nature, carrying any sort of 
female except one with a triangularly shaped abdomen and which bore all the marks of 
a peeler, or, more rarely, a soft-shelled female with a broad abdomen. If a female of the 
former sort is removed from the male and kept in a float, molting occurs,and the broad 
abdomen is acquired. Dissection shows that in such a case copulation has not yet oc- 
curred. If the male be carrying asoft-shelled female, it will be found that copulation is 
in progress or has just been accomplished. 
Copulation.—lf the female in the peeler state is left with the male, however, copu- 
lation ensues as soon as she has molted and while yet soft. The author observed 
one pair of copulating crabs which were found in a float. The female was lying on 
her back on the bottom of the float, with the abdomen extended backward, thus exposing 
the openings of the oviducts (Pl. XLIX, fig. 16). The male stood above her, with the walk- 
ing legs partially clasped about her body and with the two intromittent organs (Pl. XLIX, 
figs. 14 and 15,) inserted in the openings of her oviducts. Opportunity was not given 
for observing the beginning or concluding stages of the copulatory act. 
Hay @ states that the male frees the female as she actually begins to molt, stands 
near by during the process, and seizes her again at its completion. A reliable crabber, 
@ Hay, op. cit., p. 405. 
