MOLLUSC A OR UNIVALVES. 215 



The shells of this genus, if placed upon their 

 mouths, will stand steadily in that position, 

 with the axis very much inclined. They are 

 brought from China, India, Africa, &c. The 

 Turbo litoreus*, or common periwinkle, is used 

 by mankind as an article of food, and is found 

 on the shores of England in great numbers. In 

 Sweden, where they also abound, they serve to 

 prognosticate the approaching state of the 

 weather ; the peasants having observed that 

 whenever the periwinkles ascend the rocks it 

 is a sure sign of a storm being near, as their 

 instinct teaches them to place themselves out 

 of the reach of the dashing of the waves ; on 

 the contrary, when they make a descent upon 

 the sand it is an indication of a calm. In hot 

 countries some species are often seen on the 

 trees near the coast, and on the rocks elevated 

 above the surface of the water; they remain 

 stationary on the latter during the hottest 



* Ferussac has introduced a new genus, of which the 

 T. litoreus is a species. He names it Littorina. The 

 shells are known from Turbo and Phasianella by having 

 a horny operculum, and from Trochus by having few 

 whorls. The shells are found on the shore, whence 

 the name. 



P 4 



