OCEAlSr GABDENS ; 



ner, by expectorating the whole of the intestines and 

 leaving their case or shell bare and empty. But Sir 

 J. Dalzell has observed that the shell thus deprived 

 of its living inmate, must be much more intimately 

 connected with its life and organization than the 

 shells of the Molluscs; for after a considerable 

 lapse of time, he observed that the rejected parts 

 have been renewed by gradual growth. The intro- 

 duction of a single drop of fresh water will at once 

 drive the creature to this summary mode of putting 

 an end to the inconvenience. 



OE THE NAKED OR SHELL-LESS MOLLUSCS. 



The Sea-Lemon, Doris tuberculata^ is one of the 

 most attractive. It derives its popular name from 

 its peculiar form, which is like that of half a Lemon 

 cut longitudinally. It is generally of a yellow tone 

 of colour also, which greatly adds to the fancied 

 resemblance. It has its breathing apparatus ex- 

 posed externally, like other Nudibranchs, spreading 

 over the mantle, near the head, in a flower-like 

 shape ; and, as it moves slowly roimd and round 

 the Aquarium, forms a very singular object. 



The Doris pilosa is a pretty white species of the 

 same order ; and the little black shining Nudibranch, 

 HtmcinaSancociyh a pretty and interesting creature. 



90 



