27 



form of a marginal slit, or of a mere sinus j the shells, too, are uniformly 

 smaller. Two very small forms may be added, possessing good distinctive 

 characters, Cemorla {Patella Noachiua, Linn.), with an inner shelly cham- 

 ber, inhabiting our northern seas, in which the slit is diamond-shaped, and 

 situated, as it were, in the neck of the subspiral vertex ; and Rimula, in- 

 habiting the seas of the Philippine islands, in which the slit is situated 

 midway between the vertex and the margin. Both were known to geolo- 

 gists in a fossil state before living specimens were collected. 



The coloured Emarginulce are chiefly from Australia and the Philippine 

 Islands. On our own shore the genus is well represented, in addition to 

 the Cemoria* by three elaborately cancellated species conspicuously fissured 

 at the margin. 



1. acuminata, Adams. 



2. alveolata, id. 



3. annulata, id. 



4. Arabica, id. 



5. aspera, Gould. 



6. Blainvillei, Befr. 



7. cancellata, Phil. 



8. Candida, Adams. 



9. carinata, id. 



10. catillus, id. 



11. clathrata, Ad. 8f R. 



12. cognata, Gould. 



13. conica, D'Orb. 



14. crassa, Sow. 



15. crassilabrum, Ad. 



16. cratitia, id. 



17. cucullata, Gould. 



Species. 



18. cuvirostris, Desh. 



19. denticulata, Ad. 



20. depressa, Blainv. 



21. exquisita, Ad. 



22. fastigiata, id. 



23. fissura, Linn. 



24. fissurata, Chemn. 



25. fungina, Gould. 



26. galeata, Adams. 



27. galeata, Gould. 



28. Huzardii, Payr. 



29. imbricata, Ad. 



30. lata, Quoy. 



31. Noachina, Linn. 



32. nodulosa, Adams. 



33. notata, Linn. 



34. octoradiata, Gmel. 



35. parmophoroidea, Quoy. 



36. polygonalis, Ad. 



37. princeps, Gould. 



38. propinqua, Ad. 



39. pumila, id. 



40. reticulata, Chemn. 



41. rosea, Bell. 



42. rubra, Lam. 



43. rudis, Adams. 



44. sculptilis, id. 



45. scutellaris, id. 



46. stella ta, id. 



47. striatula, Quoy. 



48. sulcifeva, Adams. 



49. tricarinata, Bom. 



50. Vanicorensis, Quoy. 



* " This very curious shell was first observed as a fossil by Linnaeus himself, in tbe pleistocene 

 beds of Sweden. Not until of late years has it been taken alive, and British cabinets were for 

 a long time supplied with specimens froni the pleistocene beds of the Clyde. Mr. Smith, of 

 Jordan Hill, was the first to maintain its existence in the living state in the British seas. Ex- 

 cept on the Northumberland coast, where it has been taken at Cullercoats by Mr. Alder, and in 

 fifty fathoms sixty miles to the east of the north coast of Durham by Mr. King, its localities are 

 all Scottish. It ranges in depth from twenty to one hundred fathoms, and occurs at intervals 

 throughout the Hebrides and off the coast of Zetland. It is a species essentially of northern 

 origin, and has now its chief habitats in arctic aud boreal seas, exteuding along the coast of 

 Greenland, and down those of boreal America to Cape Cod. It dates its origin from the plei- 

 stocene epoch, and can only be regarded as a lingerer in our existing seas." — Forbes and Man- 

 fey, Brit. Moll., vol. ii. p. 476. 



