WOKMS. 



135 



These also fulfil a douUe purpose, inasmuch as they are used by 

 the tapeworm for attaching itself to its host, and readily accounts 

 for the difficulty experienced by dog-owners in expelling that portion 

 of the parasite. 



Of the commonest tapeworms affecting the dog the following may 

 be named"! 



Tcenia serrata. — This tapeworm, which attains about a yard in 

 length, is very frequently met with, and particularly in those 

 kennels in which the viscera of rabbits occasionally enter into the 

 dietary. The reason for this is not far to seek : the rabbit and the 

 hare are intermediaries, as they are termed, and it is in them that 

 the parasites pass a portion of their existence, usually termed the 



^ 



Section of Gid Tape- 

 worm Cyst. 



Fig. 25. Head op Gid Tapeworm as 

 found in the cysts. 



larval one, and beyond which no further development takes place in 

 that particular animal. In the hare and the rabbit this parasite 

 takes up its abode in the peritoneum, and is known by the name of 

 Cystiaereus cellulosus. 



Tmnia marginata. — The dog derives this tapeworm from the 

 Cystieereus tenuieollis of our sheep and cattle. 



Tcenia ccsnurus. — This parasite grows to a length of 1yd., and 

 sometimes more, and in the hydatid or bladder forms develop on 

 the brain of the sheep, causing " gid "or " sturdy. " In this stage of 

 its existence it is known as Cmnurus cerebralis. Dogs feeding on the 

 heads of sheep that have had the "gid' swallow these hydatids and 

 in two to three months the tapeworm is again fully developed in 

 the dog. 



