•26 
consists of a cephalic x>ortion, Tchich is extremely motile and which is defined from 
the rest of the young worm by a ridge: 
situated an ox>ening through which the 
next generation < cerc-arite > escapes. The 
posterior portion of the Avorm is provided 
at about the border of the third and last 
fourths of the bc>dy with two projections. 
There is a mouth with pharynx situated 
at the anterior extremity, the phaixiix 
leading into a simple blind intestinal sac. 
The redia. as well as the spor<x:yst. may 
l:>e looke<i upon as a female organism. an«l 
in its IxMjly cavity are found a number of 
germ cells, which develop into imiividuals 
of the next generation known as — 
fi Ceroiri.se i figs. 2S-30 . — These or- 
ganisms are quite similar to the adult 
parasites into which they later develop. 
The body is flat, more or less oval. an<l 
provided with a tail inserted at the pos- 
terior extremit}-. The oral sucker and 
acetabulum are present as in the adult, 
but the intestinal tract is verA' simple; on 
the sides of the body are seen two large 
glands, but the c*omplicateii genital organs 
of the adult are not visible. The cercaria 
Fig. 2i.— Eedia ot the redia throucrh the birth open- 
Common Liver Fluke. . ... • , 
Avith developed cer- i^g. remains m the snail lor a longer or 
earite. x 150. i After shorter time, or passes out of the body of 
Leuckart. is>9. p. 270. snail and swims around in the water. 
■ After a time it attaches itself to a blade of 
grass I flg. 29 i or some other object, and forms a cyst around 
itself Avith material from the large glands, at the same time 
under the latter is 
Fig. 2S. — Free cercaria 
of the Common LiA er 
Fluke, showing rwo 
suckers, intestine, 
large glands, and tail. 
After Leuckart. ISSO. 
p. 279. fig. 1:17. 
Fig. 29. — Portion of a grass stalk Acith three encapsuled cexcari* 
of the Common Liver Fluke i Fasciola hepatica). x 10. After 
Thomas, 1SS3, p. 291. fig. 13.) 
losing its tail. It now 
remains quiet until swal- 
L>wed by some animal. 
Then upon arriving in 
the stomach — < >f a steer, 
for instance — the cyst 
is destroy el. and the 
F IG. 30.— Isolated ency-ted 
cercaria of the Common 
Liver Fluke, x 150. 
After Leuckart. 1SS9. p. 
2S6. fig. 142. 
young parasite wanders through the gall ducts, or, as some believe, through the 
portal A’eins to the liver, where it deA*elops into the adult hermaphm^Iite. 
