60 LIMPITS. 



almost entirely upon this humble food. In the Isle of Syke, 

 the inhabitants are often, at one time of the year, without 

 any otlior source of provision." Tlicn comes the Sea-gull, 

 and the Duck, and the Pied 0)-ster- catcher, to feed on the 

 poor little mollusk, the bill of the latter bird being admirably 

 adapted for loosening its hold on the rock. 



Patella in Latin signifies a salad-dish, a knee-pan, and 

 several other domestic utensils, of a broad shallow make, 

 and hence we find the plural form of the word applied to 

 the Limpit tamily, whose shells are of such a shape. Mem- 

 bers of tliis family are found on all rocky coasts, except those 

 of the Arctic seas; on Tropical rocks they grow to a large 

 size, and form a valuable article of food. A. \Qr\ curious 

 piece of mechanism is the tongue of the Common Limpit, it 

 is from two to three inches long, and has a spoon-like ex- 

 tremity, so that it looks, when extended from the mouth, 

 like a small snake; if examined through a microscope, it is 

 seen to be armed throughout its whole extent with rows, 

 four deep, of sharp hooked teeth, and between each row are 

 placed two others, which have three points, and are set 

 in a slanting position; the use of this arrangement we cannot 

 at present detennine, but no doubt it has a perfect adaptation 

 to the wants of the animal. 



There are shell-fish called Xey-hole Limpits, which belong 

 to the genus FixsitrelU(he, from Jissura — a cleft or slip, from 

 whence comes also fissure. All the members of this genus 

 are distinguished by the aperture at the top of the shell, 

 shaped like a key-hole, which is situated exactly over the 

 breathing organs, and sen-es as a channel for the water 

 necessary for respiration. 



frequently upon the fronds of the large olive sea-weeds may 

 be found a tiny shell shaped something like that of the Com- 

 mon Limpit; it is of an olive green colour, with blue streaks, 

 and is called, from its clearness, the Pellucid Limpit, P. pellucida. 

 There is also another much like it in appearance, which natu- 

 ralists call P. /avis. To the labours of these little mollusks, 

 according to Dr. Harvey, may be partly attributed the de- 

 struction of the gigantic Algff, (sea-weed.) Eating into the 

 lower part of the stems, and destroying the branches of the 

 roots, they so far weaken the base, that it becomes unable 



