136 



of more solid growth, having a porceUanous surface with tlie umbilicus 

 filled up by a callous deposit. The first of these affect a northern latitude, 

 and are amongst the most conspicuous of the molluscous fauna of Green- 

 land and Spitzbergen; they exhibit little variety of colouring and no 

 pattern, being mostly of a uniform yellowish olive or pale brown. The 

 last are apparently inhabitants of a warmer region, of more striking colours 

 and prettily striped ; the M. tmniata, for example, is encircled by fillets of 

 bright red, and the M. pidchella by alternate bands and lines of dark 

 violet blue. 



1. acuminata, Sowerly. 



2. arctica, LeacJi. 



3. carnea, Sowerly. 



4. costellata, id. 



5. expansa, id. 



6. Groenlandica, Bech. 



Species. 

 7. minutissima, MigJiels. 13. taeniata, Sowerly. 



8. pulchella. Reeve. 



9. sigaretina, Sowerby. 



10. Solariifonnis, id. 



11. striata, Brod. h Sow. 



12. sulcata, Sowerly. 



14. umbilicaUs, Br. % Sow. 



15. uudulata, Sowerly. 



16. violacea, King. 



17. vulgaris, Leach. 



Figure. 



Margarita pulchella. PL 14. Fig. 69 and 70. Shell, showing the 

 base and callous deposit at the umbilicus. — ¥rom Mr. Cuming's col- 

 lection. 



Genus 7. TURBO, Linnaus. 



Animal ; disk short, thick, bearing at its hinder ecctremity some- 

 times a horny, mostly a calcareous operculum ; head cylindra- 

 ceous, proboscis-shaped and truncated in front, tentacles situated 

 a little in arrear, with the eyes elevated on short pedicles at 

 the outer base. 



Shell; turbinated, rather thick, sometimes umbilicated, interior 

 silver-, rarely golden-, pearly, whorls more or less rounded, 

 rough or smooth, mostly spirally ribbed, with the margins dis- 

 joined. 



The animals of Turbo, Troclms, Bel/pUnula, Margarita, and Monodonta 

 are so nearly sunilar that much difference of opinion has prevailed amongst 

 authors as to the propriety of separating them. The head has a blunt pro- 

 boscis-like form, with the tentacles a Httle beliind, bearing the eyes on 



