172 THE AMERICAN NATURALIST. [Vol. XXXVIII. 



same time in transferring sperm, but this was not directly 

 observed. During the whole process of union the male is in a 

 state of excitement while the female is quite the reverse, as far 

 as could be judged. The action of the male in turning and 

 adjusting the female is greatly assisted by the state of passivity 

 simulating death that overtakes her soon after being seized by 

 the male. This inertia of the female extends even to the 

 respiratory movements, which seem absent in strong contrast to 

 the condition in the male. The female seems to be dead and 

 the only signs of the continuance of life that were seen were the 

 movements of the eye-stalks in cases where the efforts of the 

 male led to his claws coming against the eyes and, at times, 

 a slight convulsive tremor in the abdomen, possibly connected 

 with sperm trajisfer. The very small first pair of abdominal 

 appendages which lie often against the annulus and have no 

 probable use unless it be in connection with the phenomena of 

 union, may convey sensory stimuli and occasion the above 

 abdominal contractions. On the other hand the male is in a 

 strongly excited state during the entire period of union : when 

 the struggle and turning have ceased there are still quick vibra- 

 tions of the anterior maxillipeds and strong currents of water 

 thrown out from the gill chamber as well as the long continued 

 contractions of the limb and abdominal muscles and probably 

 those of the internal male organs. The process terminartes 

 when the male moving backward and rising up crosses his fifth 

 log back again under him into its own side. He then releases 

 the female. 



'I'lic annnlns.— Thus the result of union of male and female 

 is the storing up of sperm within the annulus or sperm receptacle 

 of the female. This is in strong contrast to what has been 

 described as taking place in the European crayfish, Astacus, 

 which has no annulus; for French observers state that the 

 male distributes sperm masses, or spermatophores, over large 

 areas of the under side of the female. On the other hand in 

 the American lobster a transfer like that in Cambarus doubtless 

 takes place since Bumpus discovered the sperm-containing 

 receptacle upon the female. 



The structure which serves in the lobster to hold sperm is, 



