NOTES ON THE COMMON LIMPET. 19 



and on the same spot ? There can be little doubt 

 that any other mollusc, applying its soft parts in 

 the same manner on the rock as constantly, would 

 have the same result. Mr. J. C. Hawkshaw says : 

 "I notice signs that lim]3ets do j)refer a hard 

 smooth surface to a pit in chalk. On one face of a 

 large block over all sides of which limpets Avere regu- 

 larly and i)lentifully distributed, there were two flat 

 fragments of a fossil shell about three inches by 

 four inches embedded in the chalk. The chalk all 

 round these fragments was free from limpets, but 

 on the smooth surface of the pieces of shell they 



were packed as closely as they could be 



I noticed another case which almost amounted, to 

 my mind, that they prefer a smooth surface to a 

 hole. A limpet had formed a clearing on one of 

 the seaweed-covered blocks before referred to. In 

 the midst of this clearing was a pedestal of flint 

 rather more than an inch in diameter standing up 

 above the surface of the chalk. It i)rojected so 

 much that a tap from my hammer broke it off. 

 On the top of the smooth fractured surface of this 

 flint the limpet had taken up its abode. The shell 

 was closely adapted to the vmeven surface, wliich it 

 would only fit in one position. The clean surface 

 below was in a hollow with several cavities where the 

 limiDet could have found a pit ready made to shelter in, 

 yet it preferred after each excursion to climb up on 

 the top of the flint, the most exposed spot in all 

 its domain." * This shows very decidedly in this 

 case that the limpet prefers a hard surface to a 

 soft one ; and one would scarcely think it would 

 select a hard flint to bore in. 



I find on the sandstone rocks that when the 

 animals get larger they seem to have a tendency to 

 go lower down, and the shells get less jagged on 

 the edges. As they reach a well-matured size they 

 become thicker and plainer on the edges, and in 

 consequence it becomes more difficult to find a sur- 

 * Journ. Linn. Soc, xiv. 410. 



