PLATE LXXIX. 



Mr. Keate ; and lastly, during the summer months of 1800, was 

 taken in a moat near Portsmouth, by J. Laskey, Esq. of Cre- 

 diton, who favoured us with some particulars respecting the ani- 

 mal inhabiting it. In a young state, he says, it has the appear- 

 ance of a winged insect, and sports in its watery element with 

 all the liveliness of a butterfly, and formed a pleasing object when 

 kept alive in a glass of sea water. It seems to prefer little 

 pools, or still waters within reach of the tide, to more exposed 

 situations. 



In general die specimens that have been found at Portsmouth 

 are very small, the shell from which the upper figure is copied 

 far exceeding the others in size. This species, though very thin 

 and brittle, is yet so elastic as to bear much compression with- 

 out injury, and in this respect differs from every other British species 

 of Bulla already known. Amongst the foreign kinds are several 

 elastic kinds ; and this very species is found of a much larger 

 size in the Mediterranean Sea. — Independent of its elasticity, the 

 convoluted apex is a material character of this shell, considered 

 as a British species. 



