81 



Genus 21. RICINULA, Lamarck. 



Animal ; similar to that of Purpura. 



Shell ; orbicularly or fusiformly ovate, most frequently tuberculated 

 or spined, spire sometimes very short and depressed, sometimes 

 acuminated ; aperture rather narrow, columella a little exca- 

 vated, sometimes wrinkled or toothed, lip toothed within, teeth 

 nodulous or plait-like, edye of the lip sometimes but rarely digi- 

 tated. 



In adopting the genus Bieinula, winch has been abandoned by several 

 continental authors, I propose to include a much wider range of species 

 than has been hitherto referred to it ; namely, that fusiform series distin- 

 guished from the true Buccinum and Purpura by the inner nodulous den- 

 tition of the lip, arranged by M. Kiener as a section of the latter genus 

 under the significant title of " Les Pourpres serni-ricinules", and of which 

 the P. fiscellum of authors may be regarded as the type. It cannot be dis- 

 puted that there are species in the genera Ricinula, in its limited acceptation, 

 and Purpura, in which it is not easy to define any generic difference, as 

 for example, between the P. hystrix and the R. arachnoides, or between the 

 P. aperta and certain varieties of the R. clatlirata, but the alteration of 

 names in familiar usage should as far as possible be avoided. A large pro- 

 portion of the species recently characterized by me as Ricinula were not 

 hitherto named, and their connection with the Purpura, proper is so appa- 

 rently remote, that I have preferred elevating the genus under consi- 

 deration into one of more importance, to the creation of a new genus, or to 

 the fusion of the whole into one after the manner of the French naturalists. 



The animal of Ricinula is similar in most respects to that of Purpura, 

 already described, the head being flattened and prolonged at each corner 

 into the tentacles, and bearing a small elliptical operculum at the posterior 

 extremity of the disk. 



Species. 



1. acuminata, Reeve. 8. bicatenata, Reeve. 15. concinna, Reeve. 



2. alveolata,(P«/y;.)Kien. 9 carbonaria, id. 16. contracta, id. 



3. arachnoides, Lamarck. 10. cavernosa, id. 17. crocostoma, id. 



4. armillata, Reeve. 11. chaidea, (Purp.) Duel. 18. dealbata, id. 



5. aspera, Lamarck. 3 2. chrysostoma, Deshayes. 19. deformis, id. 



6. astricta, Reeve. 13. clathrata, Lam. 20. digitata, Lamarck. 



7. bella, id. 14. concatenata (Mur.),h. 21. echinata, Reeve. 



M 



