94 



THE GENESIS OF SPECIES. 



[CHAP. 



head of a bird, with an upper and lower beak, the whole 

 supported on a slender neck. The beak opens and shuts 

 at intervals, like the jaws of the pedicellarise of the echi- 

 nus, and there is altogether, in general principle, a remark. 



A POLYZOON WITH BIRD'S-HEAD PROCESSES. 



able similarity between the structures. Yet the echinus 

 can have, at the best, none but the most distant genetic 

 relationship with the Polyzoa. We have here again, 



