348 



MANUAL OF ZOOLOGY. 



ing arm on the left side, and to terminate in an oval plate 

 (fig. 145). To this terminal plate the spermatophore is pro- 

 bably transmitted, but the arm itself probably remains perma- 

 nently attached to the animal. It is asserted, however, that 

 in the form figured below (Octopus carend] the hectocotylised 

 arm is detached and deposited in the pallial chamber of the 

 female ; being reproduced after each generative act. In Tre- 

 moctopus the third right arm of the male is " hectocotylised," 

 and is converted into a vermiform body, with two rows of 



Fig. 145. 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 

 Woodward.) 



ventral suckers, and an oval appendage or sac behind, which 

 contains spermatozoa. Besides the suckers, the anterior part 

 of the back is fringed with a number of so-called " branchial " 

 filaments. 



In the Argonaut 'the male is not more than an inch in length, 

 is devoid of a shell, and has its third left arm hectocotylised. 

 This arm is developed in a cyst, which is ruptured by the 

 movements of the "hectocotylus," which then appears as a 



