Development of the Liver-Fluhe. 
445 
into a short intestine, whilst towards the opposite end two short 
blunt processes grow out at the sides (Fig. 4). The sporocysts 
have now reached almost their 
l ull size, and they measure -6 mm. 
Fig. 4. 
in 
are 
length. They 
very irregular form, 
often 
of 
owing to 
the protuberance of the thin 
body-wall, caused by the de- 
veloping germs. 
By the end of the thirteenth 
day the rediae are ready to issue 
from the sporocyst ; they have 
now a more elongated form, and 
may measure as much as '21 mm. 
in length, by "ll in breadth. 
The surface of the body is 
covered with a delicate struc- 
tureless cuticle, and a little way 
behind the pharynx the surface 
is raised up into a ring en- 
circling the body, whilst near 
the opposite end are the two 
short stumpy processes. These 
are not on directly opposite sides 
of the body, but are nearer to- 
gether, inclined nearly at right 
angles to one another. Beneath 
the cuticle is a granular layer 
forming the body-wall, in which 
flattened polygonal cells can be 
made out ; and beneath these, 
strongly developed muscle fibres 
arranged in two layers, the outer 
layer of transverse being much 
stronger than the inner layer of 
longitudinal fibres. The pha- 
rynx is distinct, and the diges- 
tive tract is a simple sac, the 
blind end of which reaches a 
little way past the middle of the body. The whole of the 
space between the digestive tract and the body-wall is occupied 
by round nucleated germinal cells. The young redia shows 
active movements, and at length breaks its way through the 
wall of the sporocyst. The wound produced by its forcible 
exit closes up at once, and the germs still remaining continue 
to develop. The liberated rediae begin to feed on the tissues 
of their host, and some of them at least migrate into the other 
Adult sporocyst of Liver-fluke, containing several 
germs in different stages of development. The 
largest has assumed the character of a redia. 
Magnified 230 diameters. 
