282 



ZOOLOGY 



in certain Earthworms, another in a Myriapod (Glomcris 

 limbatus). 



Taenia canurus of the Dog has a bladder- worm stage in the 

 Sheep and Rabbit which gives rise to several tape-worm heads, 



Fig. 223.— Cyst of Taenia echinococcus with the developing daughter-cysts and scolices. 



(After Lcuckart.) 



and the same holds good of Taenia serialis from the Fox. But 

 the best known instance of multiple production of scolices in a 

 cysticercus is Tamia echinococcus — well known as cause of the 

 disease termed hydatids, common in Man and in various domestic 

 animals. In this case the hooked embryo develops into a large 



mother-cyst, from the interior 

 of which daughter-cysts are 

 budded off (Fig. 223). Event- 

 ually from the walls of these 

 daughter-cysts there are 

 formed numerous tape-worm 

 heads, or scolices (Figs. 224 



Fio. 224.— Scolices of T. echinococcus. 



(After Cobbold.) 



Fig. 225. — Separate scolex of 

 T. echinococcus. (After 

 Cobbold.) 



and 225), which, when fully formed, assume the appearance of 

 cysticercoids without the caudal vesicle. These are readily de- 

 tached, and, should the organ in which the cyst has been 

 developed be devoured by a Dog — which is the final host of the 

 parasite — some of these scolices become attached to the wall 



