marine British Shells and Animals. |. 187 
more conspicuous. This specimen was considerably larger, being 
three quarters of an inch in diameter. 
Tbe shell, or Bulla tentaculata, is so extremely similar to Bulla 
Haliotoidea, that the figure of it has been omitted as üseless, since 
it could not convey the nice distinction; and the shell to which 
it is so nearly allied has already been given in Testacea Britannica, 
together with the animal to which it belongs. It is rather de- 
pressed, and more opaque than the shell of L. Haliotoidea, but 
would not be generally discriminated independently of the animal. 
To the animal, therefore, we must look for the actual identity of 
its shell; and by so doing no confusion will occur, since there is 
a material distinction between Lamellaria tentaculata and L. Ha- . 
liotoidea ; the colour is different, especially the more extended 
membranous margin of the superior lamina of the former, which, 
with the long and slender tentacula, are obvious marks of distinc- 
tion. In the few specimens examined there did not appear to be 
any arm or appendage asin L. Haliotoidea, and yet a similar sinus 
in the anterior margin of the upper lamina indicates an occa- 
sional protrusion of some similar process, which may possibly be 
only exerted in the season of love. A comparison of the figure 
which accompanies this, with that of the animal of Bulla Halio- 
toidea in the vignette of the second part of Testacea Britannica, 
Jig. 6. will be sufficient for future discrimination. 
The discovery of this species so recently in the same place with 
the last described, after such repeated examination of. the spot 
for so many years, is an additional proof of the inexhaustible 
stores that lie hidden in the deep, and that by some fortuitous 
circumstance are brought to light. Of this species very few have 
been taken; but as none of the genus appear to possess any 
great powers of locomotion, it is probable they have their natu- 
ral beds, where they congregate in great abundance, (a circum- 
VOL. XI. se | | stance 
