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. 



TurbeUaria are, with few exceptions, hermaphrodite, and 



FiQ. 60. — The reproductive organs of 

 _12 Mesostoma Ehremhergii. After R. 



Leuckart, slightly altered. 



1. Pharynx. 



2. Common male and female genital 



opening. 



3. Ovary. 



4. Yolk gland. 



5. Shell gland. 



6. Beceptaculum seminis. 



7. Uterus with eggs. 



8. Testis. 



9. Vas deferens. 



10. Vesicula seminis. 



11. Penis. 



12. Outline of alimentary canal. 



their female reproductive organs are complicated by the egg 

 being formed from two sets of glands. The ovum, with its 



