TUBIFEX. 399 



Fig. 18. (a) Longitudinal section through the ciliated 

 funnel of an immature worm. x 250. 

 (b) Transverse section of the same. x 250. 



Fig. 19. (a) Transverse section of ciliated portion of 

 vas deferens. x 800. 

 (b) Transverse section of non-ciliated portion 

 of vas deferens. x 800. 



Fig. 20. (a) Longitudinal section through ciliated 

 portion of vas deferens. x 800. 

 (b) Longitudinal section through non-ciliated 

 portion of vas deferens, x 800. 



Plate V. 



Fig. 21. Longitudinal section of vas deferens. The 

 section shows the transition from the ciliated 

 to the non-ciliated part of the duct, x 800. 



Transverse section of the retracted penis, 

 x 570. 



Transverse section of the spermathecal duct, 

 x 360. 



An oocyte from the ovisac, undergoing matura- 

 tion, x 160. 



An unusual form of the ovary which was 

 liberated from the body and drawn in the 

 living condition. 



Longitudinal section through a portion of the 

 ovary, showing pear-shaped oocytes. x 480. 



Longitudinal section through a portion of the 

 ovary, showing typical young and older 

 oocytes, the latter just before their separa- 

 tion from the ovary. x 280. 



A A 



Fig. 



22. 



Fig. 



23. 



Fig. 



24. 



Fig. 



25. 



Fig. 



26. 



Fig. 



2T. 



