NOTES ON THE COMMON LIMPET. 13 



trude beyond the shell, the longest and strongest 

 corresponding well with projecting ribs of the shell. 



The speed that I have seen the limpet attain on 

 the side of the glass was one inch in the minute, 

 and probably it can do much more. The greatest 

 distance I have seen it travel was thirty inches. I 

 never sa^v it out browsing longer than two hours 

 at a time, frequently much less ; and it never 

 seemed to be much on the move except when 

 browsing. The chief food of the limi^et api3ears to 

 be algae. I have only had an opportunity of seeing 

 it feeding on the fine filamentous kind groAvn from 

 the spores on the wall of the glass jar. I have noticed 

 with regard to those in tide pools, where the bot- 

 tom was covered with Melohesia, that their shells 

 were more opaline than any I had seen elsewhere. 

 Whether that circumstance arose from their feeding 

 on the Melohesia I am not i3repared to say. I have 

 often noticed in tide x^ool*5 that the bottom was 

 thickly covered with Melohesia, except the exact spot 

 a limpet was on, Avhich w^as always quite bare ; and 

 the Melohesia may have been prevented from grow- 

 ing by the presence of the limpet, or have been 

 used by the limpet for food; but the latter supposi- 

 tion is not so probable, as the alga surrounds the 

 shell closely and is absent only under the shell. 

 Wliether the limpet can subsist on other than 

 vegetable food seems yet an open question. 



The limpet I had in confinement was at first put 

 into a clean glass jar, and to all appearance with 

 pure sea-water. It was twelve days afterwards 

 before a vestige of sea-weed was noticed on the side 

 of the jar ; yet, as the animal was regularly passing 

 faecal matter, we may presume that it must have 

 been getting food of some kind, possibly plant 

 spores. Forbes and Hanley state that "although 

 capable of moving about with facility when well- 

 grown, it appears to become lazy and sedentary, often 

 living in crevices, where having once lodged it remains 

 till it becomes too large to come out. In such cases it 



