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 Camharus 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 Camharus, as Andrews points out, retires for a 

 number of days to the dark comers 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 taU, 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. 



o Pearce, A. S. Observations on copulation among crayfishes, with special reference to sex recognition. The American 

 Naturalist, vol. xi,m, p. 746-753. New York, 1909. 



