412 PYRAMIDELLIDAL. 
be alive in the immediate vicinity ; their numbers, and often 
fresh and excellent condition, are sufficient proof; and we 
have offered what may be the solution of the difficulty of 
obtaining them alive *. 
With respect to the so-called Odostomia turrita of authors, 
much discussion and difference of opinion have lately existed 
as to whether it is a distinct species, or a variety of an esta- 
blished one. It is inferred, from the specimens being more or 
less spirally striated throughout, that it is a good species. 
My own opinion has changed more than once: at one time I 
thought it might be an aberrant variety of Chem. insculpta ; 
in this I am mistaken: again, I had made up my mind that 
it could not belong to Chem. acuta; in this point I am also 
mistaken, as it turns out to be scarcely a variety of that 
common species; it is one of the individuals with the more 
inflated volutions. I have forty specimens, which I took the 
trouble separately to submit to the microscope, and in those 
which were not worn, I was agreeably surprised to receive the 
solution of this problem, by finding that every recent shell 
was finely spirally striated throughout ; in some the strize were 
more apparent, and easily seen by a Coddington lens; in 
others the microscope was required, and with ordinary powers, 
even in the most apparently glabrous shells, the spiral lines 
became conspicuous. In the shells that have not been much 
rubbed, the striz have acquired a crassitude by exposure to 
the air, as is always the case, which renders them more 
visible; I have such; but in the perfect recent ones they are 
excessively fine, and cannot be detected without considerable 
optical assistance. This is the simple history of the so-called 
C. turrita, which certainly is nothing more than the Chem. 
acuta with the striz somewhat more apparent than usual; 
such are in our cabinet, and malacologists will find that they 
have not a perfect recent specimen of the C. acuta which is 
not more or less spirally striated throughout. This question 
may be considered finally settled. I have had the advantage 
* Since this was written, Chem. elegantissima and the distinct Chem. 
pusilla have occurred alive in tolerable abundance; they are largely 
described. 
