PARASITES OP ANIMALS. 63 



Dracunculus medinensis Cobbold. Sub-cutaneous tissues ; in 

 tropical- Asia, Africa, and America. 



ACARINA. 



Pentastoma tcenioides Rudolphi. Nostrils ; not rare. Larvae 



in man and cattle. 



That thousands of lambs and sheep are annually killed by 

 dogs that have a taste for mutton of their own procuring is 

 unfortunately too well known to most of the farmers in this 

 country, especially in those States where neither stringent 

 laws nor severe taxes have diminished the numbers of these 

 useless curs. 



That the number of dogs in every part of the country is by 

 far too great, and even dangerously so, is generally admitted, 

 especially during the summer, when mad dogs and hydropho- 

 bia are the constant theme of conversation in our cities. That 

 the laws of every State ought to impose restrictions, or, at 

 least, very high taxes upon the owners of dogs is evident and 

 advocated by many legislators. Yet it is not, by any means, 

 generally known to what an alarming extent our flocks are in- 

 jured in health and depreciated in value by the parasites de- 

 rived directly from dogs. Still less is it known to what an 

 extent human lives and health are sacrificed on account of 

 these animals. 



There are three principal and very important parasites of 

 sheep derived from tape-worms of dogs. These are : 1. The 

 " water-brain" of sheep, which is produced by the young or 

 larvas of a small tape-worm (Tcenia ccenurus) ; 2. The ech- 

 inococcus, or hydatid tumors of sheep, of cattle, and of man, 

 found Jn various organs, but most commonly in the liver, 

 brain, and kidneys, which are caused by the young of a very 

 small dog tape-worm (Tcenia echinococeus) ; 3. The diving 

 bladder-worm, or u water-bladder," often found in the abdo- 

 men of sheep, cattle, and pigs, frequently forming tumors as 

 large as a hen's-egg, or even a goose-egg, which is the young 

 of a larger tape-worm of the dog (Tcenia marginata). There 

 are, also, others of less importance obtained by sheep from 

 dogs, as indicated in the lists. 



