THE NAUTILUS. i 
reticulated structure as a background the animals would be 
scarcely distinguishable, like the Sargassum fish (Pterophryne 
histrio) in the gulf-weed (Sargassum). 
Cyrena carolinensis Bosc. (9). In making a bridge across a 
small branch of the St. Sebastian River I first discovered this 
species. It was a large and interesting variety in which the 
umbones were unusually high, many of the specimens closely 
resembling in size and form the figure of C. olivacea Carp. from 
Mexico, as given by Prime (Monograph American Corbiculidae, 
p. 17, fig. 12, 1865). Although the tide flowed freely up the 
little creek, there was at low tide a small stream of fresh water 
even at the driest time. At the junction of this little stream 
and the high ground there was a small colony of Neritina lin- 
eolata Lam. (JN. reclivata Say). I looked in vain for this species 
during my recent visit, nor did I find Cyrena near the little 
bridge, but it may still exist in other parts of the stream which 
time did not permit me to examine thoroughly. At the mouth 
of Pellican creek near the Matanzas Inlet was a colony of 
Neritina virginea Linn. They were the olive-green or more 
brackish water type and probably represent the most northern 
limit of this species on the Atlantic coast. About seven miles 
south of Matanzas Inlet was a large cypress swamp in what was 
known as ‘‘ Bike’s Hammock,’’ here was found Ampullaria 
depressa var. hopetonensis Lea, which seems quite distinct 
from those of the St. Johns River drainage. There were 
also fine specimens of Ancylus peninsulae Pils. & Johns.—erro- 
neously referred to A. filosus in my list. The east coast canal 
has drained much of this section now called Bikes Prairie 
on the coast survey chart. In many places I saw truck 
arms as I passed through the canal on my way north from 
Daytona. 
These notes suffice to show some of the changes that can take 
place in a limited area in a comparatively short time, and the 
probable effect of such changes on certain species. It is not at 
all peculiar to St. Augustine, for similar changes are going on 
at many other places along the coast and in the vicinity of our 
cities. The importance of a careful study of a local fauna can- 
not be too strongly urged. The destruction of the forests, the 
