4.72 CLASS ECHINODERMATA. 
cupper a little farther behind, under the belly. The species 
are extremely numerous ; some are found even in the comb of 
the eye of some birds. But it also appears that some are not 
intestine, but inhabit at large the fresh and salt water. 
The most celebrated is, 
Fasciola hepatica, L., Scheef., Monogr., Copied., Encyc. 
Vers., pl. Ixxx. i. ii., which is so common in the hepatic 
vessels of sheep, but is also found in those of many other 
ruminantia, of the hog, of the horse, and even of man. Its 
form is that of a small oval leaf, pointed behind, having in 
front a small contracted portion, at the end of which is the 
first sucker ; this opens into a sort of cesophagus, from which 
some canals proceed, ramifying through the entire body, and 
carrying thither the bile on which this animal is nourished. 
A little backwards is a small retractile tentaculum, which is 
the penis ; and immediately behind that is the second sucker. 
Some spermatic vessels, very much folded, fill the middle of 
the leaf. The ovary, which is found in all the individuals, 
is enchased in the intervals of the intestines, and the eggs 
issue through a convoluted canal, which ends at a small 
hole on the side of the penis. These animals couple reci- 
procally. 
This worm multiplies greatly in sheep when they pasture in 
humid grounds, and occasions dropsy and death. 
M. Rudolphi makes a division which he names ECHINOS- 
TOMA, of the species which have in front a small enlarge- 
ment, armed with hooks. 
HoLostoma, Nitzsch., 
Have a moiety of the body concave, and so disposed as to 
act altogether as a cupper. Their orifices otherwise appear 
similar enough to those of distoma. 
Some of them are found in certain birds. ‘There is one in 
the fox. 
