218 POPULAR BRITISH CONCHOLOGY. 



the head, neck, and body alternately contracting and expand- 

 ing ; while the dorsal sack was constantly opening and shut- 

 ting its edges, and the singular apparatus within showing a 

 perpetual and curiously varying activity. These animals 

 die shortly after being taken out of the sea; and, although 

 some of them have been brought up to me without delay in 

 sea-water, I have never had the time, even if 1 possessed 

 the ability, to draw their figure. Nor is there any artist 

 here that I know of who is at all capable of doing justice to 

 subjects of this description, of which there are here many 

 hundreds, probably of the most interesting kind. I must 

 not omit to mention that this Ajdj/sia^ though apparently 

 dead, afforded a liquor which, applied to linen, soon changed 

 it to a good purple hue.^' 



The head of the Ajdysia is distinct, and variously shaped, 

 and furnished with four ear-shaped tentacles ; the body is 

 oval, convex above. When there is a shell, it is placed over 

 the breathing apparatus on the back of the animal, and 

 covered by a lobe; the mantle is spread out into a large 

 flap on each side, which can- be folded over the back so as 

 to cover it, or be used as very efficient paddles in swimming. 

 The projecting mouth is armed with horny jaws, and the 

 foot is large, flat, and oval. Such is the mollusc, to which 



