148 A. OKA. 



Bas. iiiembr. Basement membrane. 

 Tr. mu.s. Transverse muscular fibres. 

 L. mus. Longitudinal muscular fibres. 

 Lin. epitli. Lining epitbelium. 

 A'^ac. Vacuole. 



.F((j. 8. Longitudinal section of the epistome, with the ganglion 

 and the excretory organs. B x 4. 

 Gang. cav. Ganglion cavity. 



Fig. 0. Cells of the upper half of the œsophagus. F x 2. 



Fig. 10. Cells of the lower half of the œsophagus. F x 2. 



Fig. 11. Section of the cardiac valve. B x 4. 



Fig. 12. Cross section of stomach. 



Fig. 13. Cells of the inner layer of the gastric wall. F x ::^. 



pyr. c. pyramidal cells. 



cl. c. club-shaped cells. 

 Fig. U. Cells (jf the rectum. F x 2. 

 Fig. 15. a. Diagram showing the extent of the mesentery. 

 h. Section of the mesentery. D x 2. 



Fig. 16. Cross section of a tentacle. F x 2. 



Fig. 17. Longitudinal section of the tentacle. F x 2. 



Fig. 18. Diagram showing the base of tentacles. 



Fig. 19. Diagram showing the direction of the currents of the 



perigastric fiuid. 

 Fig. 20. Cells floating in the perigastric fluid. F x 2. 



Figs. 21, 22, 23, 24, 25, 26. Sections at various levels of the upper 

 portion of a polypide. B x 4. 



Figs. 21 A, 22 A, 23 A, 24A. Sections of the excretory organs. F x 2. 



Fig. 26 his. Entire form of the excretory organs. 



