THE EVOLUTION OF SEX 



25 



special receptacle within the circle of arms of the female, 

 or plants them within the mantle chamber itself of the 

 female. Each packet of spermatozoa is contained in a 

 long tube. On coming in contact with sea water the 

 tube everts at one end, and allows the sperm to escape. 



Fig. 11. — Octopus, male showing hectocotyl arm {ha). Cop- 

 ulation (below), small male, A; large female, B. 



After separation the female deposits her strings of 

 eggs, which are fertiUzed by the sperm escaping from 

 the spermatophores. In octopus and its allies, one 

 arm, that is used to transfer the spermatophores, is 

 specially modified at the breeding season (Fig. 11). 



