MOLLUSCA : CEPHALOPODA. 



423 



force. During the congress of the sexes the male transfers 

 the spermatophores to the pallial chamber of the female, true 

 intromission not being possible, but the mode in which this 



fig. 227. i. Octopus carena (male), showing cyst in place of the third arm. 2. Ven- 

 tral side of an individual, more developed, with the hectocotylus (a). (After Wood- 

 ward.) 



transference is effected differs in different cases, and is not 

 universally known. 



In the males of many of the Cuttle-fishes, one <?f the arms is 

 peculiarly modified, and is said to be " hectocotylised," but the 

 extent to which this modification is carried differs in different 

 cases, and it is not always the same arm in different species 

 which is thus affected. In some cases, the " hectocotylised " 

 arm is little altered from its ordinary form, and though the 

 alteration be primarily sexual, the arm is not known to play 

 any part in the reproductive process. In other cases, again, 

 such as Octopus carena (fig. 227), Tremoctopus violaceus (fig. 

 228, b), and Argonauta argo (fig. 228, a), the "hectocotylised" 

 arm is the efficient agent in the impregnation of the female. 



