NATURAL HISTORY OF AMERICAN LOBSTER. 
303 
Three other cases of copulation were witnessed, and in every instance between a 
soft-shelled female and a hard male and always within a few hours after the female had 
cast. In one instance when the water in the pond was run off the body of the male was 
left partly exposed. I have already noticed two cases in which the American female 
lobster was impregnated when in the soft condition and when she also bore eggs; but 
there are other facts which show that molting is not necessary for the impregnation 
of the female. In the case of the American species we have found females of all sizes 
from 8 inches and upward in length impregnated at all times of the year, and the adult 
female lobster when taken from the sea, in whatever condition of shell, is likely to have 
her receptacle well supplied with sperm, even when preparing to molt. On the coast 
of Massachusetts in June and July I have found lobsters with newly laid eggs and a 
lobster with brood just hatched and about to shed, with receptacles full of sperm, which 
was in the first instance certainly, and in the last probably, newly acquired, and when 
the shell was hard. We know that the sperm is endowed with great vitality; that it 
can endure for months, and possibly for years. It is further probable that copulation 
is more or less indiscriminate, and more than one union is sometimes necessary to secure 
the fertilization of a given hatch of eggs. 
Pearce “ has presented strong evidence to show that crayfishes have no power of 
discriminating sex, his conclusions being based upon Cambarus blandingi acutus Girard, 
C. diogenes Girard, and C. virilis, observed in confinement. “The male,” says Pearce, 
“tries” every crayfish which it meets, whatever the sex, a female instinctively remaining 
passive, while a male attempts to escape. The sexes meet by accident in the course of 
their random movements in the search for food. Males were found to even copulate 
with dead females, and in one instance with a female of another species, when the male 
stylets were inserted in the usual way in the copulatory pouch or annulus. 
After taking into account all the facts at present known it seems highly probable 
that the lobsters are actuated by similar instincts when breeding and that they possess 
no greater powers of discrimination. 
The probable method of transfer of the spermatophores is considered in a later 
section. 
PREPARATION FOR EGG LAYING-CLEANING BRUSHES IN THE LOBSTER. 
Preparatory to laying, the female Cambarus, as Andrews points out, retires for a 
number of days to the dark corners of her abode and is busily engaged in cleaning the 
under side of her abdomen for the reception of the fresh cargo of eggs. Her attitude 
and behavior in this instinctive act are peculiar. Standing as upon a tripod on the 
tail fan and the tips of the great claws, with her body raised high above the ground, she 
picks, brushes and scrapes every particle of dirt from the swimmerets and under surface 
of the tail, using chiefly the last pair of walking legs, the modifications of which, espe- 
cially in the last two joints, render them very effective, combining as they do in one 
instrument the advantages of pick, comb, and brush. 
® Pearce, A. S. Observations on copulation among crayfishes, with special reference to sex recognition. The American 
Naturalist, vol. xi.ni, p. 746-753. New York, 1909. 
