Illustrations of British Sea- Shells 153 



Figs. 3, 4. Fissuvellq reticulata (= F. grceca). White, tinged 

 with green, with about five to eight brownish-grey rays. 

 Apex of the shell perforated in adult specimens, entire and 

 subspiral in young ones. 



Figs. 5, 6. Acmeea vivginea. Greyish-white or horn-colour, 

 with radiating pinkish lines. A. testudinalis (the "tortoise- 

 shell" limpet) is variegated or reticulated with brown and 

 white. 



Figs. 7, 8. Cerithium reticulatum (— Bittium veticulatum) . 

 Brown, solid, ornamented with tubercles. Operculum spiral 

 corneous. 



Figs. 9, 10. Trochus zizyphinus (= Calliostoma zizyphinus). 

 Yellowish flesh colour, or reddish-brown, with pinkish-red 

 blotches or flame-shaped markings. 



Figs. 11, 12. Trochus cinerarius (= Gibbula cineraria). Ash 

 colour, with transverse iron-grey lines. 



Fig. 13. T. umbilicaris (= G. umbilicata). Greenish- white 

 or yellowish, with purple-red stripes. 



Figs. 14, 15. Skenea planorbis. Pale olivaceous, or reddish- 

 brown. Minute, hence often escapes notice. 



Figs. 16, 17. Littorina rudis. Smaller than the " peri- 

 winkle," from which it also differs in the rounded whorls. All 

 members of the genus have a pyriform corneous operculum. 



Figs. 18, 19. L. neritoides f more or less black, generally 

 dull and eroded. 



Figs. 20, 21. L. littoralis (= L. dbtusata), Solid, flattish ; 

 colour, variable, yellow, rufous or brown, sometimes banded. 



Figs. 22, 23. Lacuna pallidula. Thin, whitish, with a dull 

 yellow epidermis. 



Figs. 24, 25. L. puteolus (= L.parva). Body whorl, banded 

 white and chocolate-brown ; apex sometimes violet. Epi- 

 dermal covering yellowish horn colour. L . vincta (= divaricata) 

 is oblong-conical, with many minute spiral lines on the body 

 whorl. 



Figs. 26, 27. Rissoa parva. Distinct in the curved and 

 oblique chestnut-brown line on the upper corner of the outer 

 lip. Ground colour very variable. 

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