396 PYRAMIDELLIDZ. 
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 thgir 
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 Hulima, which, though 
closely allied to Chemnitzia, is nevertheless distinct in various 
points to be mentioned. M. Lovén’s Aclis next succeeds as a 
Pyramidellidan genus, and only embraces one or two species. 
Stylifer 1s admitted provisionally. The natural position of 
this genus of one species requires further investigation, which, 
from its rarity, | fear may long be delayed. 
