30 



THE INTERNAL PARASITES OP 



practically important to illustrate the separate peculiarities 

 of the measles side by side. Here, therefore, I have 

 given an enlarged view of one beef measle within its 

 cyst, accompanied by magnified representations of the 

 head of the beef and pork tapeworms respectively. The 

 measle shows a stout, laminated, fibrous envelope, which 

 consists of layers of connective tissue, the latter belonging 

 to the flesh of the host; whilst, in the interior of the 

 capsule, the head and neck of the cysticercus are readily 

 seen through the transparent, bladder-like caudal vesicle. 

 The head is apparently inclosed within the bladder, but 



A B 



Fig. 8. Measle and Tapeworm Heads. 



it is in reality outside the vesicle, a portion of which has 

 become depressed to admit the head, after the fashion of 

 an inverted finger of a glove. We term this involution 

 the " receptaculum capitis.'''' The caudal vesicle is very 

 thin, but it displays minute specks, which are due to the 

 presence of calcareous corpuscles ; these bodies being 

 much more abundant in the substance of the head and 

 neck. The head exhibits four large suckers, equidistantly 

 arranged in pairs at the angles of the square-shaped 

 head; and under favourable circumstances we may 



