396 PYEAMIDELLID^E. 



concur with M. Philippi in not using this appellation, in con- 

 sequence of the pre-occupation of the term. Though we 

 believe Dr. Fleming's genus Odostomia has the priority of 

 time, yet, from the variableness and instability of the prin- 

 cipal conchological character, the fold on the pillar, it cannot 

 be maintained either generically or as a group : for instance, 

 the Odostomia interstincta often has the fold, and often is 

 without it ; the O. indistincta never has a tooth ; the O. exca- 

 vata is sometimes with and sometimes without it. Many of 

 the more elongated and turreted species are without a fold ; 

 nevertheless in some, for instance the O. acicula, the tooth is 

 present, and often wanting, as our cabinet will show ; there- 

 fore the appellation of Odostomia to this tribe is incongruous 

 and a complete misnomer. The term cannot even be admitted 

 as a sectional arrangement, as it would separate individuals of 

 the same species, for example the toothed interstincta and the 

 edenticular one ; on these accounts we are reluctantly obliged 

 to decline the use of the term. Besides, we believe that this 

 fold or tooth has had attributed to it far more generic value 

 than it deserves : it probably gives some support to the body 

 as a point d'appui ; but the malacology of the animal, whether 

 with or without it, affords no corresponding variation. We 

 therefore propose to adopt M. D'Orbigny's genus Chemnitzia 

 for those species with or without a tooth, smooth or plicated, 

 many or few volutions, which have as a component of their 

 specific characters a moderately long, retractile proboscis, and 

 eyes at the internal bases of the tentacula. All these species 

 cannot be mistaken, as whatever may be the specialties of the 

 animals, they have the apical one or two turns reflected on the 

 following descending one. This is a constant character; I 

 have never met with a departure from it. 



The next genus of this family is Eulima, which, though 

 closely allied to Chemnitzia, is nevertheless distinct in various 

 points to be mentioned. M. Loven's Aclis next succeeds as a 

 Pyramidellidan genus, and only embraces one or two species. 

 Stylifer is admitted provisionally. The natural position of 

 this genus of one species requires further investigation, which, 

 from its rarity, I fear may long be delayed. 



