THE AMERICAN LOBSTER. 
35 
THE PAIRING OF THE LOBSTER AND OF OTHER CRUSTACEA. 
The copulation of the lobster has never been seen, as far as I am aware, in any of 
the species, but we know that it takes place in spring and summer at least, if not at 
other times of the year. If ripe females, or females even with newly laid eggs, are 
examined in June or July at Woods Hole, the seminal receptacle is found to be almost 
invariably charged with spermatozoa, and it is evident that copulation takes place, 
certainly in many cases, without immediate reference to the condition of the animal. 
Thus on August 19 I examined a female lobster which was 9 inches long and found 
her seminal receptacle loaded with sperm. The ovaries were of a light, greenish -yellow 
color, and in a very immature condition. This lobster had been impregnated at least 
two years before her eggs would be ripe. 
I was surprised to find the seminal pouch of another lobster, which was examined 
about the same time, to be charged with freshly deposited sperm, although it had just 
hatched a brood and ivas preparing to molt. It therefore seems probable that the 
male lobster lias no means of discriminating the sexual condition of the female. This 
lobster, in the ordinary course of nature, would soon have lost in the molt the sperm 
with which she had been so recently supplied. The first copulation, which had occurred 
either before or shortly after the hatching of the brood, must have been followed by a 
second union in order to secure the fertilization of the next batch of eggs. These 
would not be due, moreover, until one year from this time. It is thus evident that 
the female lobster is not impregnated once for all and compelled to take the chances 
of fertilizing her eggs, but is approached more than once by the male. The molting 
of these animals, although subject to less variation in the adult female than in the 
male, renders this necessary. Females usually molt shortly after the hatching of a 
brood. Where the molting is accomplished just before the eggs are laid, which 
happens very rarely — I have noticed only two cases in the lobster- — (see p. 80), copu- 
lation can precede the act of extrusion by a few days at the most. 
A lobster which had been kept in an aquarium for upward of two months in the 
summer, without access to the male, laid eggs which were normally fertilized. This 
and other facts which have just been mentioned show that the female lobster must in 
some cases be impregnated more than once before each reproductive period, and also 
that the spermatozoa retain their vital activities for a long time, perhaps, as Bumpus 
suggests (30), from one to two years. This is not so remarkable, when w onsider 
the longevity of spermatozoa recorded by Sir John Lubbock (Weismanu’s Essays, 
vol. 1, p. 52), who succeeded in keeping a queen ant until she was 15 years old, 
during which time she continued to lay fertile eggs. Fertilization must have taken 
place at the latest in the season when the insect was captured. “ There has been no 
male in the nest since then,’ 7 writes Lubbock, “ and, moreover, it is, I believe, well 
established that queen ants and queen bees are fertilized once for all. Hence, the 
spermatozoa of 1874 must have retained their life and energy for thirteen years, a 
fact, I believe, unparalleled in physiology.” 
Observations on the copulation of the crayfish (Potamobius fluviatilis) have been 
made by Gerbe (43), Chantran, and other naturalists. The latest and most detailed 
account of Chantran, published in 1872 (39), is as follows: 1 
1 In quotations from works in foreign languages, I shall give, for convenience, the English trans- 
lation. The extract can be verified, by reference to the original. 
