624 



W. S. NICKERSON, Cotylogaster occidentalis n. sp. 



Plate 33. 



Fig. 8. Transverse section of "neck" anterior to pharynx. 57 : 1. 



Fig. 9. Transverse section through anterior edge of ventral shield 

 showing embryos in sulcus at base of neck. 22 : 1. 



Fig. 10. Transverse section through ovary and anterior testis. 22 : 1. 



Fig. 11. Longitudinal section of marginal sense organ. 675 : 1. 



Fig. 12. Similar section of another sense organ. 675 : 1. 



Fig. 13. Section of marginal sense organ in protruded State. 675 : 1. 



Fig. 14. Longitudinal section of a sense organ showing course 

 of duct to exterior. 675 : 1. 



Fig. 15. Diagram showing relations of Organs in C. occidentalis 

 as Seen from dorsal side, the animal being represented as straightened 

 borizontally with the dorsal cone projected backward. Outlines of 

 animal (including ventral sucker), intestinal tract and excretory system 

 (so far as shown) in black; sexual organs in red; vitellary glands and 

 duct and Laurek's canal in brown. 



Fig. 16. Diagram to show relations of parts in intimate connection 

 with ovary as they would be seen from ventral side. 



Fig. 17. Longitudinal nearly sagittal section of an embryo of 

 G. occidentalis soon after leaving the egg. 680 : 1 . 



Fig. 18. Posterior half of section next following the one re- 

 presented in Fig. 17. 680 : 1. 



Fig. 19. Drawing made by combining parts of two adjaceut nearly 

 transverse sections of an embryo through region of pharynx and anterior 

 band of cilia. 680 : 1. 



? ; Fig. 20. Surface view of tuft of cilia as seen in tangential 

 section. 1220 : 1. 



^Fig. 21. Nearly sagittal section of anterior end of an embryo 

 showing gland cell (spine gland). 680 : 1. 



