1890.] MARINE MOLLUSCA OF ST. HELENA. 315 



and Sowerby. The latter has, correctly I think, cited P. tinctus and 

 P. alhus of Reeve as synonyms. In this category I should also place 

 P. sentis and P. textllis of the same author. 



EXPLANATION OP THE PLATES. 

 Plate XXI. 

 Fig. 1. Pleurototna {Clavus) aynanda, p. 255. 



2. ( ) alhohalteata, p. 255. 



3. {Drillia) turtoni, p. 256. 



4. {Mangilia) suhquadrata, p. 256. 



5. ( ) meUissi, p. 257. 



6. {Clathurella ?) vmUigranosa, p. 258. 



7. Murcx {Ociiiebra) alboangulatics, p. 259. 



8. Lachcsis helcna, p. 260. 



9. Cantharus (Tritotiidea) alhozonattis, p. 260. 



10. ( ) consanguincus, p. 260. 



11. ( ) Iwvis, p. 261. 



12. Columhclla {Mitrdla) saiictcB-hclenm, p. 262. 



13. Triton turtoni, p. 268. 



13 a. ; young. 



14. Natica turtoni, p. 269. 



14 a. ; operculum, p. 270. 



15. tceniata ; opercuhim, p. 270. 



16. sanct(B-hden<s, p. 270. 



17. Solarium ordinarium ; upper side, p. 281. 

 17 a. ; front view. 



17 b. ; lower side. 



18. Eidima (Subularia) fuscopunctata, p. 280. 



19. Littorina heloice, p. 283. 



20. Diala fuscopicta, p. 286. 



21. Rissoa cala, p. 288. 



22. ephamilla, p. 288. 



23. agapeta, p. 289. 



24. wallichi, p. 289. 



25. Barkeia congenita, p. 290. 



26. Triforis atlantica, p. 292. 



Plate XXII. 

 Fig. 1. Mitra {Cancilla) turtoni, p. 265. 



2. (Pusia) sanctce-helmce, p. 265. 



3. ObcUseus (Syrnola) pumilio, p. 275. 



4. Turbo (Colloiiia) adynissiis, p. 294. 



5. Basterotia oblomja ; lateral view, p. 303. 

 5 a. ; dorsal side. 



6. Lucina inconspicua, p. 304. 



7. {Codakia) compacta, p. 304. 



8. Area sancta-helencB ; lateral view, p. 305. 

 8 a. ; dorsal side. 



8 b. ; ventral side. 



9. Pecten atlanticus, p. 306. 



9 a. ; sculpture magnified. 



9 6. ; sculpture of left valve. 



10. (Janira) turtoni; right valve, p. 306. 



10 a. ( ) ; left valve. 



Plate XXIIL 

 Fig. 1. Pletirotoma (C'lavus) prolongafa, J). 255. 



2. {Mangilia) gemma, ]). 256. 



3. {Clathurella?) commuiabilis, p. 257. 



4. ( ) usta, p. 258. 



