APLYSIA. 263 



Plate I. 



[All the figures are of Aplysia punctata. Unless stated 

 otherwise the drawings are of full-grown specimens.] 



Fig. 1 . Right lateral view of the living animal in the expanded 

 condition. X \. 



Fig. 2. Left lateral view of the head of the living animal. 

 Expanded, x \. 



Fig. 3. Front view of the head of the living animal, x \. 



Fig. 4. Side view of the living animal in the contracted 

 condition. X J. 



Fig. 5. Chain of three individuals. Drawn from life from a 

 chain of five individuals seen in the tanks at the 

 Laboratory, Plymouth. The lowermost individual 

 A is acting as female only. B is acting as male 

 for A, but as female for C, while C is acting as 

 male only. The parapodium of A has been turned 

 back to show the penis of B curved backwards to 

 enter the common genital aperture of A. x J. 



Fig. 6. Shell from ventral aspect. The dotted lines represent 

 lines of growth, x 1. 



Fig. 7. The mantle and pallial complex from the dorsal 

 aspect. The parapodia have been cut close to the 

 base, and the edge of the mantle has been 

 reflected to expose the purple gland. X 1. 



Plate II. 



Fig. 8. General dissection from the dorsal side to show the 

 alimentary canal and reproductive apparatus. 

 Part of the nervous system is shown. Only the 

 outline of the liver is seen ; the remainder has 

 been dissected away to expose the coils of the 

 intestine. Stripings on the gut represent the 

 direction of the muscle fibres where these are 

 visible externally. X 2-5. 



Plate III. 



Fig. 9. Longitudinal optical section of the head to show the 

 interior of the buccal mass. The pharyngeal 

 crests, arising from the walls of the pharyngeal 

 canal, are not shown. (See Fig. 22.) x 2-5. 



