414 ENTOZOA. 
Festucaria, Schr.—Monostoma, Zed., 
Where there is but one of those organs, sometimes at the anterior ex- 
tremity and sometimes underneath the same end. Found in various 
Birds and Fishes*. 
Srricea, Abi/d.—Ampuistoma, Rud., 
Where there isa cup at each extremity. Found in various Quad- . 
tupeds, Birds, &c. + 
To this subgenus we must probably approximate the 
Caryopny.tizus, B/., 
Where the head is dilated, fringed and furnished underneath with a 
bilabiate sucker, not easily perceived. A second and similar sucker 
has been occasionally seen underneath the tail. 
One species is known, which inhabits various fresh-water 
Fishes, and particulary the Bream f. 
Distoma, Retz., Zed., 
Where there is a sucker at the anteriur extremity of the mouth, and 
acup, a little posterior to it, on the venter. 
The species are very numerous, and some are found even in 
the plaited membrane of the eyes of certain Birds, Others, how- 
ever, appear to inhabit fresh and salt water. The most cele- 
brated is ' 
D. hepatica; Fasciola hepatica, L.; Scheeff., Monog., copied 
Encyc., Vers, pl. Ixxx,1—11, It is very common in the hepatic 
vessels of Sheep, but is also found in those of various other 
Ruminantia, and of the Hog, Horse, and even of Man. Its form 
is that of a small oval leaf, pointed posteriorly, with a narrowed 
portion anteriorly, at the end of which is the first sucker, which 
communicates with a sort of esophagus, from which arise canals 
that ramify throughout the body, conveying the bile on which 
this animal feeds. Behind the sucker is a litle retractile tenta- 
culum, which is the penis, and posterior to that, the second 
sucker; extremely flexuous vesicule seminales fill up the centres 
of the leaf. The ovary, which is found in every individual, is 
set in the intervals of the intestines, and the ova issue through a 
flexuous canal that opens exteriorly by a small hole by the side 
of the penis. These annimals enjoy a mutual coitus. 
The species that infest Sheep become greatly multiplied when 
they graze in low and wet grounds, rendering them dropsical, and 
finally killing them §. 
* Rud., Hist., 11, p. 325, and Syn. 82; the Hyposroma, Blainv., are a division 
of the same, with a depressed body, and cups placed under the anterior extremity. 
Van Hasselt and Kuhl have discovered two new species in the Chelonia midas, Bullet. 
of Féruss., 1824, vol. IT, p. 311. 
7; Rud., Hist., p. 340, and Syn., p. $7. 
+ Id., Hist., pars 11, 9, and Syn., p. 127. 
§ For the other species see Rud., Hist., II, pars I, p. 357, and Syn., 92. For 
their organization see Observationes Anat. de Distomate hepatico et laxceolato of Ed. 
Mehlis, Gotting., 1825, in folio. 
