348 



Remarks on the Locomotion 



collected in the night-time than in the day. May not this be 

 the period of roaming for food, as well as when covered by 

 the tide ? 



The march of the limpet is slow and formal ; and, whenever 

 the cupping process is renewed, the posterior end of the shell 

 is brought in contact with the rock, which, if of a soft nature, 

 will receive the impressions of its denticulations, as seen in 

 the annexed sketch {Jig, 57.); which exhibits a piece of argil- 





laceous rock in my possession, on which this operation has 

 taken place. The track of this individual was visible over a 

 space of several yards, possessing the same regularity and dis- 

 position, and was further remarkable for the constant revolu- 

 tion on its left. 



The tracks of the limpet on granite and other hard rocks 

 • present at first sight the same appearances ; but on a closer 

 examination they are found to differ, as will be seen by 

 Jig. 58., which represents a rock of fine-grained siennite on this 

 coast, the surface of which was much worn and polished by 

 the action of the sea. When first observed, in 1829, a large 

 portion of it w^as traced over by these shells ; the remainder 

 was plain, and appeared varnished with a thin coating of 

 some kind of fucus, without any markings upon its surface. 

 As no Patellae were at first discovered, and the isolated situ- 

 ation of the rock prevented any from reaching it, I was at a 

 loss to explain these appearances ; but, after some search, a 

 fissure was found at the north end, where five or six limpets 



