OUR DOMESTICATED ANIMALS. 



101 



I have elsewhere characterised the larva of this parasite 

 as the Slender-necked Hydatid (The Field, Feb. 22, 

 1873). The accompanying illustration, from the learned 

 Pastor G-oeze's work, shows the hydatid (Gysticercus 

 tenuicollis) of the natural size at A (Fig. 21) ; whilst the 

 letter B represents a magnified view of the head, display- 

 ing the suckers and double crown of hooks. 



Artificial rearing of the Tcenia marginata in the dog 

 has frequently been accomplished abroad, and Mr. 

 Simonds and myself have been equally successful in our 

 experiments with this worm at the Royal Veterinary 

 College. 



Fig. 21. Larva of the Margined Tapeworm. 



The Hydatid Tapeivorm. — Of all the entozoa infesting 

 mankind and animals, the little Taenia echinococcus is one 

 of the most remarkable; and the facts of development 

 which render the parasite so interesting to the helmintho- 

 logist have an intimate bearing upon questions of general 

 and agricultural hygiene. The larvge form the common 

 hydatids or bladder worms of veterinarians (Echinococcus 

 veterinorum) . 



As in the dog the full-grown tapeworm only reaches 

 the third of an inch in length, it is difficult for the non- 



