THE CESTOIDEA 



143 



with the life-cycle of T. solium and similar forms, was that there are at 

 least three different generations involved, viz. (1) the fertilised egg, which 



5. 



6. 



FIG. XXXIII. 



gives rise by the ordinary process of development to a six-hooked embryo, 

 or " proscolex," which becomes by modification the bladder-worm, Cysti- 



