EQUINE ENTOZOA. 333 



This parasite, although occasionally found in the horse, is 

 more commonly encountered in the ass. Very few cases 

 only are recorded of this worm being found in the horse, 

 and, when present, it generally appears to be harmless. 



The life history of this interesting parasite will be more 

 appropriately treated of in works on Bovine and Ovine 

 Medicine. 



(B.) Amphistoma Collinsii and Stanleyi. — These species 

 are rarely found in the colon of horses, and are liable to set 

 up intestinal irritation. The fresh specimens are of a brick- 

 red colour, and have been sent from India. 



(C.) Gastrodiscus Sonsinonis. — This amphistome, which 

 exceeds half an inch in length and one-third in breadth, was 

 discovered by Dr. Sonsino in the carcases of solipeds which 

 died in the Egyptian plague in 1876. 



II. CESTODA, or TAPEWORMS (xscrroj, a girdle). 



This group includes not only the tapeworms, but also the 

 cystic worms. The members of this group have two 

 distinct phases of existence. In the one, the scolex of the 

 j)arasite is connected with a so-called cyst or bladder, and 

 is buried in the solid tissue of the host. In the other, 

 the adult tapeworm is found in the alimentary canal. 



The adult worm is made up of a number of proglottides 

 fastened on to a scolex, or head, which is fixed on to the 

 mucous membrane of the gut. A fully matured tapeworm 

 is thus in reality composed of a colony of zooids. 



Life-history of a Tapeworm. — When the proglottides, or 

 segments of the adult worm, become mature, they pass off 

 with the faeces. Each segment contains a quantity of ripe 

 eggs; these, becoming scattered about, may gain access to the 

 alimentary canal of a suitable intermediary host. In this new 

 situation the six-hooked embryo which is contained in the 



