^}{ecklace-shells and Winkles 



225 



Eggs of Periwinkle (magnified) 



wliich the spiral is wound 



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sexes is not so great in the present species, because 

 the female does not retain her eggs but deposits them 

 in masses upon 



weeds and rocks. y^ /P^Cc^^^ 



The colour of the / /n)^^Jk=^ 



shell is yellow- 

 brown, greyish 

 yellow, or olive, 

 with red - brown 

 or dark brown 

 bands, and flat 

 spiral ridges. 

 There are 7 or 8 

 whorls. The cen- 

 tral pillar round wliich the spiral is wouna is 

 always white. Winkles are exceedingly common 

 below ordinary high- water mark all round our coasts, 

 and thousands of tons are gathered annually and sent 

 into the towns to be sold as a delicacy among the 

 poorer classes. 



The Chink-shells constitute the genus Lacuna, 

 which is represented by four native species. They 

 are chiefly distinguished from the Winkles by the 

 fact that the lobe to which the operculum is attached 

 is large, and ends in a pair of long tentacle-like fila- 

 ments. The head tentacles are flat and smooth, and 

 the mouth of the umbilicus is a long slit in the pillar, 

 whence the names Chink-shell and LacuMa (a fissure). 

 The shell lacks the stony solidity of the Winkle- 

 shells, though the animal also feeds upon seaweeds, 

 but not so much about rocks. Loven has observed 

 that the animals are coloured to harmonise with the 

 weeds upon which they feed. 



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