86 ZOOLOGY 
the anterior end of the body, and break up into a number of 
fine branches. The nerves arising from the posterior angles 
run backwards on each side of the pharynx and stomach, 
rather ventral to the latter. Von Graff figures a transverse 
commissure connecting these two posterior nerves just behind 
the pharynx. 
A pair of eyes are situated directly upon the dorsal side 
of the brain, they are composed of two triangular aggregations 
of pigmented cells. 
Turbellaria are, with few exceptions, hermaphrodite, and 
. 60.—The reproductive organs of 
Mesostoma Ehrenbergit. After R. 
Leuckart, slightly altered. 
. Pharynx. 
2. Common male and female genital 
opening. 
. Ovary. 
. Yolk gland, 
. Shell gland. 
. Receptaculum seminis. 
7. Uterus with eggs. 
. Testis. 
. Vas deferens. 
. Vesicula seminis. 
. Penis. 
. Outline of alimentary canal. 
their female reproductive organs are complicated by the egg 
being formed from two sets of glands. The ovum, with its 
