242 Veterinary Medicine. 



ing tissue and produce more or less irritation. Two may lie side 

 by side enclosed in a common outer sac, but two heads are never 

 developed from the same inner sac, as is the case with coenurus. 

 The single head is seen as a white point through the transparent 

 sac. 



The coenurus is seen as a semi-transparent cyst developed 

 from a single proscolex, as in the case of the cysticercus, but in 

 place of a single head, it develops on its inner .surface many 

 (100 to 200) smaller sacs like large pin heads, each containing 

 its independent head which can be invaginated into its special 

 sac, or projected outward into the surrounding tissues. The 

 coenurus can, therefore, multiply in the cystic form outside the 

 ordinary mode of generation, and while a cysticercus ovum can 

 develop into but one tape-worm, the coenurus can produce 100 or 

 more. 



The echinococcus is also characterized by the power of in- 

 crease in the cystic form. The original cyst into which the 

 proscolex develops, can produce in its interior a number of 

 daughter cysts (proligerous vesicles) each of which can develop 

 several heads. The secondary cysts of the coenurus remain of 

 small size and individually develop but one head only, while the 

 secondary echinococcus cyst may grow to a large size and each 

 develop a number of heads. Thus in the echinococcus cyst it is 

 common to find several heads attached to the same entocyst, and 

 some detached and floating free in the liquid. 



It will be seen that the cysticercus taenia can increase by ova 

 only, while both coenurus and echinococcus can multiply also 

 through multiplication of the larva or cyst. 



Unarmed Tape-worms. (Anoplotsenia, a privative, oplon 

 weapon). The characteristic of this form is the absence of 

 rostrum and booklets in both larval and taenia forms. With the 

 single exception of the taenia litterata of the dog, they have been 

 found in the herbivora only, and as fully mature taenia. Their 

 migrations and their hosts in the larval or cystic form remain to 

 be discovered. 



Birds harbor a great variety of taenia, of the cystic forms and 

 migrations of which, we are as j^et in ignorance. 



Flat headed Tape-worms. (Bothriocephalus, bothrios a 

 hole, cephale, head). These are characterized first by having the 



