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Shell Life 



length, found 

 nearly round, 



among zoophytes, etc. The shell is 

 and is marked by an incised pattern 

 of dots arranged in spirals. It may 

 be found among shell-sand but is not 

 common. Another form, P. catena, 

 somewhat larger, has the ornamenta- 

 tion in the form of numerous rings 

 arranofed in chain-like series. There 

 is a broad zone more transparent than 

 the rest of the shell, and the chain- 

 like marks included in that zone are 

 more strongly defined than elsewhere. An allied 

 species, Colpodaspis jmsilla, of which only two speci- 

 mens had previously been recorded, was taken at 

 Plymouth in 1894. 

 In the Sea Hare 

 {Aplysia p-nnctata) 

 the shell is reduced 

 to a more or less 

 flat shield beneath 

 the integuments. 

 It is oblong, almost transparent, and flexible. The 

 animal is of the remarkable form depicted ; the small 

 head connected with the humped back by a long neck. 

 From the foot two ample lobes fold up 

 over the back, but they maybe expanded 

 and used for swimminfr. In the middle 

 of the back is the gill, covered by the 

 shell and a fold of the mantle which is 

 continued back to form a siphon. The 

 head bears two pairs of tentacles, the 

 hinder pair when erected resembling ears. Viewed 

 from the front, when this creature is gliding, it 



