136 ZOOLOGY 
of the capsule, and lie in its lumen. The cavity of the capsule 
also contains certain amoeboid corpuscles, and probably repre- 
is 
7h ie 
eee 
oa. 
Fig. 86.—Hirudo medicinalis, opened along the 
median dorsal line, slightly diagrammatic. A. G. 
Bourne. 
1. Cerebral ganglion. 
2. Oesophagus. 
3. Ist postoral ganglion. 
4, Penis. 
5. Epididymis. 
. Ovisacs. 
. Vas deferens. 
6 
7. Glandular enlargement of the oviducts. 
8 
9 
. 2nd pair of testes. 
10. Lateral vessel. 
11. 9th pair of nephridia. 
12, Vesicle near external opening of nephridium. 
13. 23rd ganglion. 
14. Posterior sucker. 
sents part of the coelom. The oviducts unite and pass into 
a muscular vagina, their walls are glandular, and secrete an 
albuminous fluid in which the eggs float in the cocoon. 
The segments on which the reproductive organs open form 
the clitellum, which consists of certain segments with glandular 
walls, the secretion of which hardens and forms in most forms 
a cocoon in which the fertilised eggs mature. In Clepsine the 
eggs are attached to some foreign substance, and the female 
sits over them till they hatch, and then they attach them- 
