412 THE ANIMALS AND MAN 



like sac fastened to the crab by means of the feeding root- 

 lets. Loss by degeneration of the body-parts is carried 

 very far in this case. 



Numerous other parasites live, like Sacculina, attached 

 firmly to their host, and do not move about. They are 



Fig. 205. Sacculina, a parasitic crustacean; A, attached to a crab, the 

 root-like processes of the parasite penetrating the body of the host; 

 B, the active larval condition; C, the adult removed from its host. 

 (Enlarged; after Haeckel.) 



carried by the host. Such parasites are usually without 

 wings, legs, or other locomotory organs. Because they 



