Testaceous Pneumonobranchous MoUusca of Great Britain." 523 



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 



