EXPIvANATION OF PLATE XIII. 



Fig. 



I. 



2. 



3- 

 4- 

 5- 



6. 



7- 



9- 



10. 



Side view of Prisma ahorense (nat. size). 

 Head of the animal (dorsal view). 

 Side view of the head. 

 Ventral view of the head. 



Alimentary canal and pulmonar}^ area : i, proboscis; 2, 

 radular sac; 3, salivar}^ gland; 4, intestine; 5, oeso- 

 phagus; 6kidne3^; 7, pericardium. 



Salivary gland^ X 2: a, dorsal view; h, ventral view. 



Pharynx (side view), X 2: 1, salivary ducts; 2, radular 

 portion of the pharynx ; 3, oesophagus. 



Three teeth of radula , X about 255. 

 Pedal gland, X 2. 



Male genital organ, X about 20: i, flagellum; 2, penis; 

 3, right Simrothian gland. 



