GASTKOPODA. 95 



this Class. The pretty, many-coloured Ridged 

 Winkle (Littorina rudis), congregates in hollows 

 of the rock, scarcely within reach of the spray, 

 except at spring-tides ; the Limpet adheres by 

 thousands but a little lower ; on the boulders, 

 about half- tide level, the Purple (Purpura) and 

 one or two species of Trochus may be seen ; 

 lower still, to the verge of extreme low-tide, we 

 find the purple-spotted Trochus (T. ziziphinus) , 

 the ridged and furrowed Rock-shell (Murex), the 

 Dog-Winkle (Nassa), the Chitons, looking like the 

 Millepedes of our gardens, and the lovely little 

 Cowry, enveloped in its variegated mantle. If we 

 turn over stones at the water's edge, especially in 

 spring, we may find the Sea-lemon (Doris), the 

 lovely Eolis coronata, and other species of Nudi- 

 branchs, which resort thither to lay their coils of 

 spawn, the Pleurobranclius, and the great purple 

 Sea-hare, which stains the stones with its rich 

 crimson dye. 



Many species may be found among the sea- 

 weeds. On the tangled masses of the Bladder-weed, 

 the Yellow Winkle and several of the Tops occur 

 by thousands ; the common Periwinkle haunts the 

 conferva-clad mud, as well as weedy rocks ; and 

 by gathering tufts of Corallina, Ceramium, and 

 other small but bushy Alga, and shaking them 

 into a basin of water, we may obtain crowds of 

 tiny Rissoa and their allies, together with the 

 beautiful Phasianella, and such-like small beauties. 

 The lustrous little Blue-lined Limpet (Pat. pellu- 

 cida) is found in cavities, which it has eaten out 

 of the massive stems and roots of the Tangle. 



The lanihina, with its curious apparatus of 

 swimming-bladders, floats on the surface of the 





