Testaceous Pneumonobranchous Mollusca of Great Britain." 593 
from being determined. In this, as well as the genus Patella, 
to which it is most probably allied, I have frequently observed 
individuals out of their natural element, and only occasionally 
in the enjoyment of a few spray drops of water which fell from 
the sides of the rock to which they were attached. 
XXXI. On 
