THE SHELL-DWELLERS 



193 



which looks rather hke a long, Hat Limpet, 

 hut on closer inspection is seen to have 

 its shell arranged in eight pieces or bands 

 across its hack. This is the Chiton, and 



COWRIE AND VENUS SHELLS. 



when detached from the rock tlie creatine 

 has a curious habit of rolling itself up 

 like an armadillo, so that it is sometimes 

 known as the Armadillo-shell. The eight 

 divisions of the shell are so arranged that 

 the pointed posterior edge of each over- 

 laps the one behind. 



The large and handsome Ormer {Haliotis 

 iiihercitlata) abounds on the shores of the 

 Channel Islands, and full-grown specimens 

 measure about four inches in length by 

 three inches in breadth. Its beautiful iri- 

 descent shell is frequently to be seen in 

 seaside " curio " shops, and is one of 

 the delights of every col- 

 lector. 



The Sting or Rock 

 \A'inkle. like the Dog- 

 whelk, preys upon its 

 fellow shell-dwellers, and 

 frequents the pools near 

 low-tide mark and the 

 deeper water beyond. It 

 is one of the many foes 

 of the Oyster fisherman, 

 for it delights to drill a 

 hole through the shell of 

 the Oyster and regale it- 

 self upon that succulent 

 mollusc. In the time <>l 

 the Romans a beautiful 

 purple dye was obtained fn^m a species 

 of Rock Winkle, the small shells being 

 bruised in a mortar ; and on the Tyrian 

 shore and the coast of Morea large heaps of 

 these crushed shells, together with the old 

 rough stone mortars, are still to be seen. 

 25 



" Devour and be devoured " is very nuich 



the order of life amongst the shell-dwellers. 



and the pretty little sea-snail Xatica is 



no excei)tion to the rule. Feeding largely 



upon small Mussels anti similar 



molluscs, the Natica is in turn 



greedily devoured b\' the Cod 



and Haddock. 



The Cockle, which frequents 

 sandy, gravelly shores, is a great 

 gymnast, for by smartly j)roject- 

 ing its foot against the ground 

 it can leap a distance of live or six 

 yards. Where Cockles abound 

 an extraordinary sight may be 

 witnessed as the tide begins h> 

 rise, for then the Cockles, which 

 lia\c been safely hiding in the 

 sand, emerge in large numbers 

 and begin to leap down the shore towards 

 the incoming tide. The Prickly Cockle 

 {CardiiDn echinatiim) is well worth seeking 

 for its handsome shell. It is a cousin of 

 the Common Cockle, and is to be found in 

 similar situations on the shore. 



A shell-dweller that has an almost 

 world-wide distribution is the Trochus, or, 

 to give it its two popular names, the 

 Hoop or Top shell. The animal lives in 

 the pools at about low- water mark, and 

 has a very handsome pyramidal-shaj^ed 

 shell, with a nearly flat base. 



The beautiful, lustrous white Ladder- 



Tin: I'KICKLY COCKLE 



shell. (M- Wenlle-trap. is another shell- 

 dweller that frequents the rock pools at 

 low-tide mark. The delicate spiral shell 

 is turreted and many-whorled. and is fur- 

 ther ornamented with numerous trans- 

 verse ribs. A living specimen should 



