144 POPULAR BRITISH CONCHOLOGY. 



periwinkles are often prominent, not only for their numbers 

 but also for their activity. They dot and stud the slimJ 

 rocks with their turbinated shells, or creep through the tiny 

 corallines, or slide along the overhanging fuci in search of 

 food. 



" Part single, or with mate, 

 Graze the seaweed,* their pasture, 

 And through groves of coral stray." 



Let US examine the nature of these interesting objects by 

 taking an example : here is one at rest. We see a rather 

 solid-looking shell of a dark colour, perhaps distinctly 

 banded ; at the base, on which it rests, it is rounded out ; 

 but at the apex, which is towards the eye, it is a little pointed ; 

 its surface is not quite smooth, but at a glance appears as 

 if it were so : it is L. littorea. On cruelly disturbing its 

 repose, by turning the shell over, so as to see the aperture, 

 we find that the latter has a flattish, white columella, or 

 inner edge, and that, instead of seeing at once the soft parts 

 of the animal, we find it is shut in by a horny plate or oper- 

 culum, which is spiral, but with very few, rapidly increasing 

 whorls; presently this plate begins to be raised, and then, 

 peeping cautiously between it and the outer lip of the aper- 

 ture, the tawny animal protrudes his head, which is closely 



