PERIWINKLES WHELKS. 19 



rests, it is rounded out; but at the apex, which is 

 toward 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 fiattish white 

 columella, or inner edge, and that, instead of seeing 

 at once the soft parts of the animal, we find it is shut 

 by a horny plate, or operculum, 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 aperture, 

 the tawny animal protrudes his head, which is closely 

 marked with black waved lines the muzzle is rather 

 short, broad, and straight in front the pyrarnidical 

 tentacles are ringed with the black lines they are 

 blunt-pointed at the apex, but thick at the base, 

 where they have a very thick swelling, on which the 

 bright little specks of eyes are placed. Throwing 

 back the pointed hinder part of the whitish foot, 

 which carries away the horny door with it, the 

 Periwinkle lifts his heavy shell over his back, and 

 crawling away, is soon out of sight." 



This is a graphic description of the Periwinkle as 

 he is seen on the rocks, but our most interesting 

 view of him is as an occupant of the Aquarium; there 

 he is indeed always welcome and useful. 



After your Aquarium has been established for a few 

 weeks, you will observe a vegetative growth, consist- 

 ing of minute spores of sea-weeds, collect upon the 



