PARASITES OF ANIMALS. 101 
Tenia elliptica Batsch is a similar species living in the cat, 
and by some is thought to be the same. 
' Several tape-worms of the dog have already been de 
scribed (Tania echinococcus, T. cenurus, T. marginata), 
but there is another that is equally common in some districts. 
Tenia serrata Goeze closely resembles T. cenurus and T. 
marginata. The larve live among the viscera of rabbits and 
hares, producing small round cysts, and the dogs get this tape- 
worm by eating rabbits or the refuse thrown aside in dressing 
them. The young state or larva was formerly named Cysti- 
cercus pisiformis, in allusion to the pea-shaped cysts. 
The Broad Tape-worm of Man (Bothriocephalus latus 
, Bremser). 
The genus Bothviocephalus differs greatly from the true 
tape-worms (Zenia) in many anatomical characters, but has 
a similar form of body, divided into many flat joints. The 
head has no suckers, but is long-oval in shape, with a long 
and deep groove on each side. It has no proboscis and no 
hooks. The reproductive organs open at the middle of the 
side of each joint, instead of the edge. 
There are numerous species living in fishes and quite a 
number in birds. The present species grows to an enormous 
size—probably larger than any other known tape-worm. It 
grows to the length of 25 or 30 feet, and according to some 
authors to 50 or 60 feet. It is sometimes an inch wide. The 
joints seldom break off, either singly or in chains, but the 
eggs are discharged by the bursting of the joints while still 
attached within the body of the infested person. The male 
and female organs open separately, the male organ being a 
little in advance of the female orifice. The female uterine 
organ forms a sort of rosette, with eight or ten lobes, around 
the external orifice. 
Its fertility is remarkable, even for a tape-worm. Prof. 
Eschricht found in one specimen 10,000 joints ; allowing each 
of these to contain only a thousand eggs, this worm would 
have produced 10,000,000 young. The full history of this 
parasite is not yet known. The eggs, however, will hatch in 
water, producing curious embryos, which are provided with 
vibrating cilia by megus-ofy wbichathey swim around for a 
