DB. T. S. COBBOLD ON ENTOZOA IN THE DOG. 285 



servers generally ; for lie found this entozoon in three Danisli foxes, 

 and also in a blue or Arctic fox (Canis lagopus) whicli died in Dr. 

 Kjaerbolling's menagerie. It is worthy of remark that the last- 

 named animal had originally come from Iceland. The importance 

 of noticing these particulars and of indicating all the rarer forms 

 of canine entozoa will appear in the sequel. 



4. Trichosoma plica. — This parasite, like the previous species, is 

 much more common in the fox than in the dog ; but the possibility 

 of its occurrence in the latter should be born in mind. So far as 

 I am aware, the only direct proof we have of its liability to infest 

 the dog rests upon the statements of Dr. Bellingham. The cir- 

 cumstance of its not inhabiting the alimentary canal will readily 

 account for its not having been often seen although it should 

 afterward turn out to be comparatively frequent in occurrence. 

 The organization of the species has been sufficiently well investi- 

 gated by Eayer; but its precise genetic relations remain to be 

 cleared up. It is by no means improbable that the progeny of 

 the preceding species, as well as of this entozoon and of the form 

 next to be noticed, passes through phases of development closely 

 resembling those of Trichina. Thus it may happen that an in- 

 experienced observer finding these larvae, in the act of migrating, 

 in the flesh of any "host" might be induced to conclude that he 

 had discovered examples of the fleshworm-disease, when in truth 

 he had only encountered the offspring of parasites totally distinct. 

 Mistakes of this kind have occurred over and over again in 

 reference to a minute and little-known parasite which infests the 

 cat; and doubtless nearly all the sexually immature forms of 

 parasites described as new species by their respective discoverers 

 are the oflispring only of some of their more or less familiarly 

 known representatives. 



5. TricliocepTialus depressiusculus. — This parasite is likewise 

 common to the dog and fox, and, though on the whole more pre- 

 valent in the former, cannot be said to be frequent in either. I 

 have only seen one or two examples. Out of 144 dogs dissected' 

 at Vienna it was only noticed four times ; and in sixty-two 

 foxes examined at the same place, not one was encountered. On 

 the other hand, Dujardin found this species present in two out of 

 seven foxes dissected by him at Eennes. It does not appear to 

 have come under Dr. Krabbe's observation in any of the 600 dogs 

 which he examined in Denmark and Iceland. I regret that I 

 retain no accurate data respecting the prevalence of this and 

 several other of the less frequent parasitic forms which I have 



