Marine Shells of Massachusetts. 263 
references to species. But while we are in little danger 
of undervaluing the importance, or rather the necessity, 
of specific descriptions, we may forget that this is but 
 & preparatory step to a higher object—an intimate and . 
complete acquaintance with the external and internal 
economy of the species. The description of characters 
is but an introduction, an unmeaning very without 
farther acquaintance. 
Although the following remarks make scarcely any 
advance towards this object, I have thought that it 
might be worth the while to offer them. With scarcely 
an exception, they were suggested by personal obser- 
vation of species of Mollusca, during occasional visits 
to the southeastern shores of this State. I have also 
thrown in some descriptive remarks, which seemed ne- 
cessary, after comparing the original. descriptions of 
authors with numerous specimens, which were collected 
on these shores. To Dr. A. A. Gould I have been 
much indebted for his kind assistance in — the 
species which had been described. 
. CoLUMBELLA. 
C. avdra, Sax, Journ. Acad. Nat. Sc. HI. 230. 
This Columbella of Mass. differs, but not specifically, 
from the description of Say in the Journal of the Acad- 
emy. The pigment appears only on the living shell. 
The color beneath it ranges from yellowish brown, 
rufous, to a dark reddish brown, maculated 
with. white, the. white spots being most distinct upon 
the coste. These are from fourteen to sixteen upon the 
body whorl, rarely eighteen in number. 
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