CARNIVOBA 301 



per cent. According to Krabbe the prevalence of the last-named 

 species is 57 per cent, in Iceland and 48 per cent, in Copenhagen, 

 whereas the T. serrata is almost absent from those countries. 

 The gid tapeworm (T. coenurus) is derived from the ordinary 

 gid hydatid infesting the brains of sheep and lambs. The 

 polycephalous bladder-worm (Coenurus cerebralis), so familiar to 

 agriculturists and veterinarians, is often confounded with the 

 ordinary hydatid infesting ruminants. Ccenuri infest the soft 

 parts of rabbits, but it remains to be shown whether they are the 

 same species. Possibly the Gcenurus cuniculi is merely a variety. 

 The gid tapeworm is not very abundant in England. In Denmark 

 it appears to be rare, occurring in 1 per cent, only ; but in 

 Iceland Krabbe found it in 18 per cent. In common with other 

 helminthologists, I have frequently reared this and the serrated 

 species by worm feedings administered to dogs. The lettered 

 tapeworm (T. Utter ata) is very commonly spoken of as the Tanm 

 canis lagopodis. It was so named by Viborg, but I prefer the 

 more distinctive nomenclature of Batsch. We know nothing, 

 for certain, respecting the source of this entozoon. It is rare 

 if not altogether wanting in Denmark, but abundant in Iceland 

 (21 per cent,). I have obtained specimens from a cheetah 

 ( Canis jubatus) which died at the Zoological Gardens, and Mr 

 W. H. Jackson, of Oxford, found it in a cat. The worm is 

 certainly not confined to the Arctic fox (0. lag opus.). 



A well-known tapeworm infests the fox which has not yet 

 been noticed in the dog. This is the Tcenia crassiceps, whose 

 scolices (Cysticercuslongicollis) reside in the viscera and soft 

 parts of field mice and voles (Arvicola arvalis, A. terrestris, A. 

 amphibius) . This relationship was pointed out by Leuckart. 

 Another tapeworm (T. opuntioides) mentioned by Rudolphi as 

 occurring in the wolf,*seems to be of doubtful authenticity. A 

 formidable and not uncommon tapeworm is Ttenia marginata. 

 This large species occurs in at least 25 per cent, of English dogs, 

 whilst in Iceland its prevalence reaches 75 per cent. In Den- 

 mark about 14 per cent. only. 



It is well known that the larval or scolex stage (Cysticercus 

 tenuicollis) of the margined tapeworm resides in the sheep and 

 dog. In a feeding experiment with five examples of this bladder 

 worm I reared five strobiles of ten days' growth. These imma- 

 ture tapeworms were each one inch long. By far the most 

 important tapeworm of the dog, however, is the hydatid-forming 

 species (T. echinococcus) . This remarkable entozoon is the sole 



