ODOSTOMIA. 109 



and is thus characterized : " Shell conic oval ; pillar with 

 a single tooth or fold towards the middle; operculum 

 none. Includes Turbo unidentatus and others." This 

 description, in respect of the absence of an operculum, 

 is obviously wrong. Fleming's ' History of British 

 Animals ' (1828) gave a more correct definition of the 

 present genus. The 7th volume of the ' Edinburgh En- 

 cyclopaedia ' (1830), under tfre head " Conchology," has 

 full descriptions of the genus Odostomia and of the above- 

 named species of Montagu ; but Pupa and other land- 

 shells are by some mistake confounded with them. 

 Alcide D'Orbigny's account of the Mollusca, in the 

 Supplement to Barker- Webb and Berthelot's Natural 

 History of the Canary Isles (1839 or 1840), gives Chem- 

 nitzia as a subgenus of Melania ; it is inadequately de- 

 fined, the animal being described as " inconnu," and the 

 shell as intermediate between Eulima and Bonellia or 

 Niso. The Turbo elegantissimus of Montagu (T. lac- 

 teus, L.) is the sole type of D'Orbigny's subgenus. 

 Much more precise and accurate, however, was the de- 

 finition by the Rev. R. T. Lowe, in the ' Proceedings 

 of the Zoological Society' for 1840, of his genus Par- 

 thenia, which corresponds with Chemnitzia. Three more 

 synonyms are Pyrgiscus, Philippi (Wiegmamr's Archiv, 

 1841), Orthostelis, Aradas and Maggiore (Atti Accad. 

 Gioenia, 1841), and Loxomma, Phillips (Palseoz. Foss. 

 Cornwall, 1841) ; to which may be added, in part, Ja- 

 minia of Brown (not of Leach or Risso), Turbonella of 

 Leach, and for certain species Eulimella of Forbes, and 

 Auriculma of Gray. Clark proposed, but never pub- 

 lished, the significant name Monoptaxis for the whole 

 group of species. It is evident that the generic name 

 Odostomia is prior to all the others which I have enume- 

 rated ; and I am inclined to think that the definition 



