550 R. T. GUNTHER. 



FiG. 7. — Radial section through an entire spermarium (sp.) and through a 

 portion of the radial canal on which the spermarium is situated. 



Fig. 8. — Section through a portion of the wall of the spermarium of 

 another individual, a — t are various stages in the development of the 

 spermatozoa. 



Fig. 9. — Endodermic lining of the oral end of the manubrium (Region I). 



Fig. 10. — Endoderm of the middle or region II of the manubrium. 



Fig. 11. — Section through the wall of Region III of the gastro-vascular 

 cavity. Note the much vacuolated nature of the ordinary digestive cells of 

 this region, and also the numerous goblet gland cells {ff. c), each filled with 

 numerous granules of secreted matter, a; is a foreign particle undergoing 

 intra-cellular digestion. 



Fig. 12. — Section through an upper corner of the gastro-vascular cavity, 

 showing the junction between the endoderm of Region III, figured in Fig. 11, 

 and the small-celled endoderm of the subumbrellar roof of the gastro- 

 vascular cavity. 



