CIIEMNITZIA. 241 



been most generally used of late as most convenient. To 

 this we assent, and deem it a sufficient reason, for, assuredly, 

 the name Turhonilla comes much too near the names 

 of other mollusks with which the shells before us have 

 no affinity. 



But in adopting this restricted genus at all, we are 

 acting reluctantly in opposition to the views of several 

 eminent authorities who have devoted much and special 

 attention to the group and its allies. 



Professor Loven, in an excellent paper published in the 

 proceedings of the Royal Swedish Academy for 184G, 

 combines the mollusks composing the group Chemnitzia 

 and Odostomia, under the name Turhonilla of Leach, and 

 gives a full and strict definition of both animal and shell. 

 Mr. Jeffreys, in his paper cited before, takes the same 

 view, but extends to the whole assemblage the name 

 Odostomia given by Dr. Fleming to the toothed species. 

 Mr. Alder and, we may add, Mr. Clark are inclined like- 

 wise to regard the Odostomia, Chemnitzia, and JEuIimella 

 as one. The last mentioned name was given by Pro- 

 fessor E. Forbes to certain smooth and polished forms 

 previously referred to Chemnitzia. 



There is no question that the animals of all these shells 

 are very similar to each other, INIoreover there can hardly 

 be a question about the small value which should be at- 

 tached to the presence or absence among them of a fold 

 on the columella. But the polished and, as it were, 

 enamelled surface of the shell in the majority of so-called 

 Odostomia, and in all the Eulimella, is a character as- 

 suredly of consequence as a point of structure, and con- 

 spicuously accompanies other features. In the fanuly of 

 Pyramidella, the structure of the shell is assuredly of 

 generic importance in other instances, and we hold it to 



VOL. III. I I 



