OUR DOMESTICATED ANIMALS. 81 



means a correct one ; but I have, thus far, purposely- 

 dwelt at great length on those forms of entozoa which 

 are in some sense or other injurious in their action upon 

 mankind, through the medium of certain of our domes- 

 ticated animals. 



With this brief explanation I pass on to notice the 

 Parasites of the Dog. 



It is surprising what a number of entozoa infest the 

 dog ; and it is still more remarkable to observe what a 

 number of creatures, including man himself, are destined 

 to play the vole of intermediary bearer of the canine para- 

 sites in their juvenile stages of development. It is this 

 consideration which to my mind renders the dog, in the 

 matter of parasitism, far more important than any other 

 domesticated animal that can be named. 



It is not a little singular that a trematode parasite 

 which I had the good fortune to discover at the Zoological 

 Society's Menagerie fourteen years ago has recently been 

 re-discovered, so to speak, in India. The worm in ques- 

 tion may be termed the Conjoined Fluke. 



This species (Distoma conjunctum) was originally 

 obtained by me from the liver ducts of an American red 

 fox (Canis fulvus) , in which situation it had given rise to 

 inflammation and the formation of small cysts or ab- 

 scesses, apparently causing the death of the host. Its 

 average size was about one-fourth of an inch in length. 

 Evidently speaking of this entozoon, Dr. Lewis remarks 

 that it is " not unfrequently met with in the bile ducts ' } 

 of the pariah dogs of India ; moreover, if the accom- 

 panying illustration (Fig. 16, a; reduced from a drawing 

 by Dr. Lewis) be compared with that given in the second 

 plate of my larger work, it will be clearly seen that the 

 specific identity of the worms is complete. It is true that, 



a 



