monograph op the genus strophia. 
121 
No. 3 is a heavy shell, shorter and thicker than is the type, 1.10 
by .40, with a thick double margin (.10), short, prominent central tooth 
and very narrow projecting frontal bar. The shell is white, mottled 
with very pale brown. Of this singular form I have two only, and 
they came from the northward of the type locatity. 
Strophia einerea may at once be distinguished from all other 
members of the genus by the thin margin, thickened slightly to the 
left, which is produced well forward, cylindrical form and peculiar 
color. No other Strophia, with which I am familiar, combines these 
characters in one species. 
This species, being from an accessible locality, is quite common in 
collections, but in all of the cases where I have seen it labled it has 
ei roneously borne the name of some of the older species which are 
from widely different localities. 
The species has been known for many years, and we find it 
figured by Edmund A. Crouch, in his introduction to Lemarcke’s 
Conchology, in 1827, plate XV, No. 2, as S. mumia ! (See remarks 
regarding this on page 194 of Vol. I..) 
HABITS AND DISTRIBUTION. 
This singular and interesting Strophia occurs on Hog Island, 
along the shore of Middle Bay, which is on the south side of the key! 
The shells are found either on the ground or attached to the stems of 
low bushes not far above the ground. I traced them about a hundred 
yards along the bay in either direction ; to the eastward they straggle 
out somewhat and grow into form No. 2, but to the westward 
terminate more abruptly, and do not occur far up the slope of the hill, 
which lies to the northward, excepting as stragglers, to be mentioned 
under head of the next sub-species. 
31 STROPHIA CINEREA ROBUSTA Novo. 
Robust Strophia. 
Fig. 36, A, front view ; B, side view of type. 
DESCRIPTION. 
Sp. Cii. Size large. Form robust. Striations, present. Whirls, 
nine. Examined, seventy-five specimens. 
Form of shell, conical ; the upper whirl being the largest, and 
each successive whirl smaller in regular proportion to the fourth, 
