266 Cenurus of the Hare. [ ZOE 
not occur in the smaller species, the Brush Rabbit (Lepus trow 
bridgei), and Cotton-tail (Lepus sylvaticus auduboni), of which I 
have examined hundreds of specimens. Although they are so fre- 
quently seen, I have never met with any one who had the slightest 
suspicion of their true nature—for these innocent-looking “ blisters ”’ 
are tape-worms in the larva stage, waiting patiently for their final 
transformation. 
Tape-worms are exceedingly common, most animals harboring 
one or more, either in the perfect or the larva state, but they are 
rare in reptiles. They are true parasites, living entirely at the ex- 
pense of their host, and repaying him in too many instances with 
disease and death. Their life history is now tolerably well known; 
those which belong properly to the carnivora, pass their larva stage 
in the flesh of some herbiverous animal which is the natural prey of 
its future host. 
Tape-worms, in their perfect form, are rather inconvenient than 
dangerous guests. They can be dislodged with comparative facility ; 
but unhappily this is not true of the larve. 
The subject of this paper is a Cenurus, a name given to those 
Tenie@, which in the larva state develop many heads from a single 
vesicle by a process of budding. It has never been described from 
the hare so far as I know, but Mr. C. B.- Rose, of Norfolk, Eng- 
land, published as long ago as 1833, an account of a ceenurus found 
in the rabbit of the warrens ( Lepus cuniculus), which may be the 
same. Further investigations, and especially comparison of the 
perfect tape-worms, are necessary to settle this question. 
The more detailed description which follows has been carefully 
made, and as the material is abundant can be readily verified by 
anyone accustomed to the use of a microscope. : 
_ On removing the skin from a hare affected with ceenurus, one or 
more swellings looking like bladders buried in the flesh, may be 
seen, ordinarily upon the loins or thighs, though they may be found 
in any part of the body. If the capsule of connective and muscular 
tissue which encloses the cenurus be now carefully opened, a quan- 
tity of clear fluid and a bladdery vesicle escape. This vesicle is 
also filled with fluid, and has attached to its outer surface many — 
smaller vesicles, and a great number, often many hundred papilla, - 
which, when fresh, are seen to be actively contracting. These 
_ papilla, milk-white in color and attached by slender pedicels to the 
