288 DE. T. S. COBBOLD OK ENTOZOA IN THE DOGt. 



infest the dog, it is generally agreed that this form is both human 

 and canine, so to speak. In either case it is believed that the 

 " host " acquires possession of the parasite by the consumption of 

 fish. Dr. Knoch, of Petersburg, believed he had succeeded in 

 rearing this species in dogs by direct experiment vdth its embryos ; 

 but the necessity of an " intermediary bearer" has been clearly 

 established by Leuckart. The presence of BotTiriocephali in. the 

 dog in this country is very rare. One such cestode may be seen 

 in the Museum of the E-oyal Veterinary College ; and no doubt 

 can be entertained that it belongs to this species. 



10. BotJiriocephalus cordatus. — This form is quite distract from 

 the above, and seems to be very abundant in the dogs of North 

 Greenland, where it also occasionally infests the human body. In 

 the dog it occurs in considerable numbers, and can scarcely fail to 

 occasion the animal more or less distress ; but we have no evidence 

 to show that it gives rise to any inconvenience in the human 

 subject, where, so far as is at present known, it either exists 

 singly or in very small numbers. Its comparative abundance in 

 the dog doubtless depends upon the more ready access which 

 that animal has to the uncooked food containing the larvae, which 

 latter are supposed to abound in marine fish. 



11. BothriocepJialus fuscus . — Dr. Krabbe, of Copenhagen, de- 

 scribed a variety of pit-headed tapeworms obtained from dogs in 

 Iceland, all of which appear to be distinct from the above species. 

 He recognizes three separate kinds {JS. fuscus, B. reticulatus, B. 

 duhius), severally presenting marked features of their own ; but he 

 is not prepared to affirm that these characters have any specific 

 value. I do not now discuss this point, but I may remark, in 

 passing, that the preparations of B. cordatus sent me by Prof. 

 Leuckart, and the specimens oi B. fuscus presented to me by Dr. 

 Klrabbe, aftord convincing proof of the distinctness of these two 

 forms. Takiug the Bothriocephali as a whole they only occur iu 

 the ratio of 5 per cent, ia Iceland, whilst Dr. Krabbe's investi- 

 gations also show that in Denmark they are very much less 

 frequent. In the 500 dogs examined at Copenhagen he only 

 found one infested. It is by no means improbable that one or 

 other of the forms will be discovered in this country. 



12. Tcenia inarginata. — The tapeworms, properly so called, are 

 far more numerously represented than the BotJiriocephali ; and 

 this is one of the commonest forms. The frequency with which 

 I have encountered it leads me to conjecture its presence in at 

 least 25 or 30 per cent, of our English dogs. In Denmark it is 



