THE NAUTILUS. 7 



reticulated structure as a background the animals would be 

 scarcely distinguishable, like the Sargassum fish (Pterophryne 

 histrio') in the gulf- weed (Sargassum). 



Oyrena 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 

 umbpnes were unusually high, many of the specimens closely 

 resembling in size and form the figure of 0. 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. (JV. reclivata Say). I looked in vain for this species 

 during my recent visit, nor did I find Oyrena 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 



