MONOGRAPH OF THE GENUS STROPIIIA. 
131 
No. 3 is a form with more numerous striations, twenty-four to the 
first whirl, and they are finer, the shell is darker, with dark umber 
blotches, which often cross the striations. 
No. 4. A short form, with nine whirls, and, excepting this, is a 
miniature of the type. Size, .76 by .86. 
No. 5. The smallest of all, with a very thin margin and with 
numerous striations, 30 to the first whirl, and the color, with )ut and 
within, is much paler than in the type. Size, .65 by ,87. 
This last form is almost sub-specific, but there still remain too 
many specimens having intermediate characters, that bind them to 
other forms, to so consider it. 
Form No. 1 is very rare, less than one per cent, of the whole. 
No. 2 is more common, about .10 per cent, of the whole. No. 3 is less 
common, about 1 per cent.; while Nos. 4 and 5 are more abundant, 
and form about five per cent, of the whole. 
Cory’s Strophia may be known by the heavy shell, thick margin, 
and peculiar brown color, with the contrasting creamy white striations. 
I have named this species for Mr. Charles B. Cory, the well 
known ornithologist, who has exhibited considerable interest in 
West Indian shells, especially in the genus Strophia. 
HABITS AND DISTRIBUTION. ' 
Cory’s Strophia is an abundant species on the extreme west end 
of New Providence, and is found clinging to bushes and herbage that 
grow along the bay. I traced it northward as far as the open grounds 
which lie about the single house that stands on this bay, and south- 
ward as far as the bushes extend, and eastward to the pine woods. 
In regard to the locality occupied by the forms, I cannot speak 
with certainty, as I did not collect all of the specimens which were 
procured, and, in fact, had a few hours only in which to examine the 
locality, as we came to anchor in the bay for a short time, when we 
■were bound for Andros. 
One of the most singular things that I have to state regarding 
this Strophia, is the fact that I found five undoubted specimens on 
Spruce Key. Two of these only were living, all the rest were dead. 
Thus on this little key, which is only a few hundred yards long, live 
two species of Strophia. 
We have seen that even among typical Strophia cinerea there is 
aninclination to evolve a white form (No. 3) and that this is quite like 
form No. 2, which is evolved by S. coryi. We also find that through 
