50 



The Endoparasitic Development of the Rhizocephala. 



These diagrams (Text fig. 13) are constructed from the actual sections drawn on Piate 5. 

 In Figures 10 and 11 (Piate 5) the invagination to forni the perisomatic space {pc) has just 



wrn. 



i 

 ■pc 



pc 



Text fig. 12. 



■vm 



.vrn. 



<T \A-c 



-Orn, 



r 



àp 



r 



Text fig. 13. 



°P 



vm = visceral mass, he = mantle cavity. pc = perisomatic cavity. op = opening of perisomatic cavity. 



begun. It always begins in the same place namely between the visceral mass of the Saccu- 

 lina and the intestine of the crab, and at the posterior part of the centrai tumour. The cells 



