PYRAMIDELLID.E. 399 



not precisely in the position of the proboscidal fissure of the 

 MuricidaB ; it is not quite so low in the fork, though exactly 

 under the tentacula at the point of the invasion of the neck, 

 and its continuation the rostrum, hy those organs. This 

 position is proved by the proboscis, when evolved, lying upon 

 the rostrum, and by its breadth equalling that of the neck (a 

 point I formerly doubted) , and entirely hiding that organ from 

 view. This leads me to say, that for the fourth time, a few 

 days since, I witnessed the emission of the proboscis from a 

 specimen of one of the slender varieties of Chem. acuta. I 

 had an excellent view, as the animal exserted and withdrew it 

 several times, which was not the case before ; it was not quite 

 so slender at the point, nor so much arcuated as in Mr. Alder's 

 figure ; its orifice was distinctly seen. 



From the above remarks and the descriptions that follow, 

 which comprise animals of the genera Chemnitzia, Odostomia, 

 and Eulimella of modern authors, I submit to naturalists the 

 propriety of merging the two latter in Chemnitzia, an appel- 

 lation that fortunately has no other significancy than that of 

 compliment to a laborious author in this branch of natural 

 history. The similarity of the organs of the animals of the 

 three genera, so far from affording essential generic characters, 

 does not suffice without the assistance of the shell for specific 

 distinction. Surely the Chem. rufa and C. elegantissima should 

 not be separated from the smoother Chem. Scillce and C. acicula, 

 merely because the one is smooth and the other is ribbed : if 

 so, to be consistent, it would be necessary to separate the 

 smooth Chem. pallida from the ribbed Chem. decussata and 

 inter stincta. As to the spiral fold, all the Chemnitzice have 

 it, though in many it does not come into the limits of visibi- 

 lity; but is that a reason to separate precisely congeneric 

 animals ? The tooth or fold, according to the species, is as 

 often absent from view in the aperture as present, and it is 

 curious that this condition is not unfrequently seen in the 

 same species. I would ask then, are the inhabitants of such 

 shells to be consigned to Chemnitzia or Odostomia? Chem- 

 nitzia, even including the Odostomite and Eulimellce, is not 

 so abundant in species as to supply an excuse for dividing 



