He N ae es, 
“I 
VOL. 111. NOVEMBER, 1889. No. 
THE VIRGINIA COLONY OF HELIX NEMORALIS. 
BY T. D. A. COCKERELL. 
Perhaps some of your readers, when they see the long list below 
of varieties differing only slightly from one another, will think it a 
ease of much ado about nothing, and wonder where the interest 
ean be in such minute differences of color or banding. 
In these days it ought to be unnecessary to apologise for going 
into precise detail in scientific matters, but I will venture to point 
out that the present case is one of quite exceptional interest. 
Here we have an exceedingly variable species, whose varieties 
have been extensively studied in its native country—Europe, and 
found to differ greatly according to locality and circumstances. 
A few of these varieties may be traced to definite causes—most of 
them appear to occur causelessly, which is another way of saying. 
that the cause is, in these cases, as yet unknown. A highly variable 
species, then, is introduced into a new continent, where climatic and 
other conditions differ markedly from those of its native home. 
It is certain to vary—it varies everywhere—will it not, then, be 
influenced in its variation by the new environment, and produce, 
perhaps, new and unheard-of forms? And if so, shall we not thereby 
have a valuable clue to the nature of these forms, and the general 
principles which underly the phenomena of variation in this and 
perhaps in other spe¢ies? In the endeavor to answer these ques- 
tions I shall feel excused, both now and hereafter, if I seem to go 
into these matters more minutely than is usual with conchological 
work. Myself, I believe that in the noting of minute differences 
