a77d Habits of the Limpet. 347 



observation, and the careful study of this neglected species^ 

 Since the observations of Reaumur on the locomotion of the 

 Patellae, the general habits of the limpet have not been so 

 clearly known as might have been expected. M. d'Orbigny, 

 junior, indeed, made some interesting remarks on this class of 

 Gasteropodes, from examinations taken on the chalky coast of 

 the Channel, where they are frequently found partly buried in 

 holes in rocks and stones, symmetrically formed by their own 

 shells; and the constant position retained by the shells in 

 these cavities has raised a doubt whether they ever left these 

 favourite spots. It may be observed, that the regularity of 

 the shells of the Gasteropodes is considerably affected by the 

 ruggedness or unevenness of the spot to which they show a 

 predilection to attach themselves ; and that the growth of the 

 shell is influenced by it, so that they frequently appear dis- 

 torted in an extraordinary manner. This singular attachment 

 to a particular spot having commenced during their young 

 state, they seldom seek another, but accommodate their shell, 

 in its after-growth, to all the irregularities of the rock. The 

 first choice of the situation appears to differ agreeably to its 

 distance from low-water mark, those animals most exposed to 

 the rays of the sun seeking a shaded side in preference. The 

 Patella having the power of raising its shell, and roving about 

 at pleasure, counteracts the influence of the inequalities of 

 the substance to which it is fixed, and does not so frequently 

 exhibit the pattern of the base as the O'strea, Anomia, and 

 Xepas are seen to do. 



The locomotion of the limpet may be ascertained by mark- 

 ing one individual, to avoid mistake, and then observing its 

 cautious roaming, and regular return to its favourite place of 

 rest, where the shell will be found exactly to correspond with 

 the surface of the rock to which it is attached. Here it will 

 rest, or sleep, and only relax its strong adhesion to the rock 

 when the muscular fibre becomes exhausted by long contrac- 

 tion, in which state a sudden blow horizontally given will 

 easily displace it. A fact known to the fishermen and the 

 poor who use them for food * is, that they are more easily 



* Patella vulgata seems to have been used by the inhabitants of these 

 islands from the earliest times, as appears from masses of its shells now 

 found in ground which has lain waste and unturned for centuries. In 1829, 

 a large heap of these shells, mixed with ashes, was discovered in a furze 

 field, about 2 ft. below the surface ; among which a leathern bag was found, 

 containing near 700 silver and copper coins of the reigns of Edward III., 

 Philippe VI. (de Valois),&c. In the ruins of the oldest buildings are found 

 great quantities of broken limpet shells (many of them retaining the marks 

 of fire) mixed with the mortar used in the building. This, however, will 

 appear the less rqmarkable in a country destitute of limestone. 



