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MONOGRAPH OF TIIE GENES STKOPHIA. 
OBSERVATIONS. 
Variation is toward a slightly larger form, but with about the 
same proportion, but with a beveled margin with lines of growth only, 
also toward a more pointed form with the first whirl the largest. There 
is also the following distinct form : 
No. 1. White in color, and with a tendency to assume a less 
number of striations. The margin is beveled and grooved, but in 
some individuals is doubled. 
This singular little Strophia may be distinguished from S. 
thorndikei, which it resembles somewhat, by the heavier shell, thicker 
margin, smaller aperture and different color. I know of no other 
Strophia which it resembles. 
HABITS AND DISTRIBUTION. 
About midway on the southern side of the western portion of Goat 
Key is a little bay, and on the western border of it is a small mangrove 
swamp. A sand beach entirely surrounds this portion of the key, 
hut along the little bay, especially to the eastward of the mangrove 
swamp, the land being low (for the mangrove swamp evidently repre- 
sents an old lagoon) the sand has encroached upon the land 
considerably. This sandy tract, however, in the immediate neighbor- 
hood, is covered with bushes, or small trees. It was on one of these 
little trees and on a few shrubs very near it that I found the colony 
of the singular little Strophia restricts. 
On Goat Key one can learn a lesson in the evolution of species of 
Strophia which will prove of great value to him. Here on this little 
spot of land, at most not over three acres, we find three distinct forms 
of this genus of shells ; and be it remembered that this island is 
distant from Little Galden Key only about a half mile, yet, as seen, it is 
impossible to assign even characters which will define a form to the 
Strophias which live on Green and Little Galden Keys, and these 
islands are about fifteen miles apart ! Facts like these have already 
caused me to remark that I feel that it is far too early in my studies 
of this genus to even speculate on the origin of many of the species, and 
more especially on the origin of all the groups, and their connection 
with one another. 
One thing is clear, however, that the Strophias inhabiting Goat 
Key were derived directly from the S. bimarginata of Little Galden 
Key. First, S. piisbryi, through this the dark, flecked S. p. evolva. 
