73 



Fig. 9a. Horizontal section of a pallial gill, x 30. 



Pig. 9b. Part of the sub-epithelial nerve plexus of a pallial 

 gill (after Haller), showing connection with sense 

 cell and multipolar ganglion cell (M. Gang. C). 

 Highly magnified. 



Pig. 10. The alimentary canal of Patella. See description, 

 page 20. Por the sake of clearness this is 

 represented in two parts, the first three coils are 

 shown in Fig. 10a and the third (Int. 1) connects 

 at X with the fourth (Int. 2) in Fig. 10b. Yin 

 Fig. 10a is the point at which the stomach folds 

 on itself. The coils of intestine are labelled 

 Int. 1, Int. 2, etc. x 1. ' 



Pig. 11. Dorsal palatal plate, x 10. 



Pig. 12. Diagram showing the radular sac, etc. Each = 



Piadula. X 3. 

 Fig 13a. Dorsal view of the odontophoral cartilages, x 3. 



Pig. 136. Ventral view of odontophoral cartilages and 

 muscles. See p. 31 for description. Some 

 muscles are supposed to have been removed. 

 Somewhat diagrammatic, x 3. 



Fig. 13t'. The inturned (median) surface of left half of odonto- 

 phore cushion. Some muscles have been removed. 

 X 3. 



Fig. 14. One row of teeth from the radula. x 25. 



Fig. 15. Diagrammatic transverse section of the gullet to 

 show the positions, etc., of the ducts of the 

 buccal glands, x 15. 



Fig. 16. Diagram of the gullet and buccal glands in a 

 specimen which had the glands unusually well 

 marked off from one another, x 3. 



Fig. 17. Section of a lobule of the hepato-pancreas (after 

 Haller). Highly magnified. 



Fig. 18. Surface of one of the transverse folds of the crop. 

 Pa^j. CV.-F. = Papilla3 of internal edge of transverse 



