104 



POPULAR CONCHOLOGY. 



the tentacula; otherwise like Litorina. Forbes has the 

 following description of this animal : — "A muzzle-shaped 

 head, with two rather short tentacula, bearing the eyes at 

 the tips ; no neck lobes ; operculigerous lobe without fila- 

 mentary processes ; foot rounded at both ends ; lateral 

 elements of the tongue dissimilar, all with denticulated 

 apices ; median denticle with extended lateral crura curves, 

 and a prominent basal process." 



A Grayana is found in brackish water in the Thames. 

 There are Indian and Chinese species. 



Litorina. Fer. — (Trochus Adanson ; Turbo Lin. part, 

 and Phasianella Lam. part.) — Shell 

 thick, with but few whorls ; aperture 

 rather round, acute at the upper part : 

 inner lip rather flat, no umbilicus ; outer 

 lip acute, thickened within ; surface 

 smooth, or spirally grooved ; operculum 

 horny, rather spiral. Animal, head with 

 a short round snout ; the eyes at the base 

 of the tentacula on protuberances; foot 

 rounded at both extremites, grooved below ; tongue with 

 lobed and denticulated tops to the teeth. — Nearly 100 

 species ; also fossil. 



The Litorina 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 ap- 

 proaching state of the weather ; the peasants having ob- 

 served, 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 



