PYRAMIDELLID ZA. 399 
not precisely in the position of the proboscidal fissure of the 
Muricide ; it is not quite so low in the fork, though exactly 
under the tentacula at the pomt of the invasion of the neck, 
and its continuation the rostrum, by 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 pomt, 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 Hulimella 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. Scille 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 
interstincta. As to the spiral fold, all the Chemnitzie 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 Odostomie and Eulimelle, is not 
so abundant in species as to supply an excuse for dividing 
