146 
the sperms are stored. 
PLAT VHELMINTHES. 
It communicates with the exterior 
by a vagina, opening close to the penis. 
Fig. 79.—HEAD of TANIA 
SOLIUM. 
(After LEuCKART.) 
Proglot- 
tides. 
Note the ring of hooks on the 
rostrum, the four suckers, and the 
commencing proglottides. 
.the exterior. 
Eggs pass down the ovi- 
duct, are fertilised by sperms 
from the seminal vesicle, 
receive yolk from the yolk- 
glands and a shell from the 
shell-gland, and then pass into 
the uterus. Here they ac- 
cumulate in enormous num- 
bers, and a “‘ripe” proglottis 
contains a large branching 
uterus with eggs; the remain- 
der of the sexual organs have 
atrophied. The eggs are at 
first surrounded by an oval 
vitelline membrane filled with 
albumen, but later this ruptures 
and the egg has merely a thick 
shell. 
The ripe proglottides are 
shed one by one and pass to 
The eggs are set 
free in millions on introduction 
of the proglottis into the stomach of a pig. The embryo is 
spherical and has three pairs of hooks. 
By these, combined 
Fig. 80.—TRANSVERSE SECTION OF A PROGLOTTIS OF TANIA. 
(After SHIPLEY.) 
Uterus. 
Oviduct. 
Ovary. 
Testis. 
Duct. 
‘Excretory 
Nerve Cord. 
Longitudinal 
Muscles, 
Ectoderm. 
