218 SHELLS AND MOLLUSCOUS ANIMALS. 



coasts, and the shore near them is often strewed 

 with its dark olive-green shells. This fish is 

 indigestible as food, though, like the limpet, it 

 forms an important article of diet to many people. 

 In some places the fish is called Pin-patch, because 

 the lid or operculum is so generally removed with a 

 pin when it is eaten. This cartilaginous substance 

 is attached to the foot of the animal within, and 

 acts as a lid or door, protecting it from the intrusion 

 of its enemies, and exactly closing up the aperture 

 of the shell. The large whelk is also furnished 

 with a strong similar lid, as are other species of 

 univalves. Some of the turbinated shells have 

 lids of this kind of a more thick and solid nature, 

 and calcareous substance, and these were once 

 much valued for medicinal purposes. Pennant 

 tells us that the Swedish peasant believes, that 

 when these shell-fish crawl high up the rocks, a 

 storm is brewing in the south ; but Linnaeus 

 quotes a Norwegian writer, who says that when 

 the periwinkle climbs thus high, it foretells the 

 coming of a land wind, and a calm in-shore. 



A shell of a dull red, or fawn, or drab colour, 

 very thick and shaped like that of the periwinkle, 

 the Turbo rudis, is not unfrequent on our rocky 

 shores. It is about three-fourths of an inch long, 

 and its outer lip thick and glossy within ; and 

 several other British species may also be found in 

 similar places. 



The foot of the animals of the genus Turbo, as 

 well as some others of this class, is so compressed 

 as to serve as a kind of paddle in the water, while 

 its breathing organs are little tufts like plumes on 

 the back. These animals feed on vegetables, and 

 are provided with a tongue, armed with very small 



