180 Proceedings of the Royal Irish Academy. 



Plate TX. 



PIG. 



7. Tiibifex Thompsoni n. sp. : 



A. Seta from anterior dorsal bundle. 



B. Brain. 



c. Terminal portion of male efferent apparatus : 



a. chitinous penis-sheath ; b. sac containing penial seta ; 



c. penial seta. 



8. Stylodrilus Halli'isyi n. sp. : 



A. Seta. 



B. Brain. 



C. Xephridium: 



a. rosette-shaped funnel ; b. glandular enlargement coloured 

 brown ; c. glandular investment closely applied to ; 



d. ventral vessel ; e. branch of ventral vessel going to 

 intestinal sinus ; f . peritoneal cells covering intestine ; 

 g. external pore. 



D. Longitudinal section of anterior end : 



a. brain ; b. testes ; c. spermatheca ; d. penis ; e. atrium, 

 covered with prostate glands ; f. sperm-sacs. 



E. Transverse section through middle of body : 



a. dorsal vessel ; b. ventral vessel giving off branch to c. the 

 perivisceral sinus; d. ventral nerve-cord; e. nephridia 

 cut through. 



F. Three sections through one of posterior segments : 



a. dorsal vessel ; b. ventral vessel ; c. blind sacs. 



G. Vascular system in the tail ; ventral view : 



a. blind sacs of dorsal vessel ; b. branches from ventral 

 vessel d. to perivisceral sinus ; c. intestine. 



