334 ANIMAL BIOLOGY. [Part II. 



host, in the muscles of which it becomes encysted, having as- 

 sumed the form of a hollow bladder-like blastosphere. The 

 blastosphere seems then to become invaginated, and within the 

 caecum so formed a pre-scolex is developed (Fig. 98, B.), which 

 by evagination becomes a scolex (C.), attached to which is the 

 blastosphere. This is known as the cysticercus stage, and the 

 organism is called a bladder-worm. The pork which contains 

 such bladder-worms is called measly. Such pork, if eaten by 

 man in an uncooked or incompletely cooked state, gives rise to 

 tapeworm. The scolex attaches itself to the intestine by its 

 suckers and circlet of hooks. The bladder seems to be lost, and 

 in its place there bud out the series of metameres which convert 

 the organism into a fully-developed tapeworm strobila. 



