THE NAUTILUS. / 



A LIST OF LAND AND FRESH- WATER SHELLS OF YEMASSEE, SOUTH 



CAROLINA. 



BY JOHN B. HENDERSON. 



In the early part of March last I spent a week upon a plantation 

 near Yemassee, Beaufort Co., South Carolina, the greater part of my 

 time being spent in snail hunting. Beaufort is a low-lying county 

 within the Atlantic coastal plain. Its features are of three distinct 

 sorts : a sandy, dry-pine area, the " knolls " of live oak with rather 

 dense deciduous vegetation, and the swamp lands. The swamps are 

 extensive, often containing forests of cypress and rank growths of 

 aquatic vegetation. In places these swamps are drained and con- 

 verted into rice fields, the latter furnishing excellent stations for 

 fresh-water mollusca. The pine lands harbor a scant molluscan 

 fauna. The great majority of land shells are to be found only in and 

 about the edges of the deciduous forests. In the depths of the 

 swamps I found almost nothing, the fresh-water species seeming to 

 prefer more open and smaller bodies of water particularly the little 

 ditches which drain the rice fields. 



The prevailing Polygyra is hopetonensis, a typical costal plain 

 species, as it ranges along the Atlantic border from Norfolk to St. 

 Augustine. It obviously belongs to the fallax-tridentata series and 

 I think is a descendant of the former, which, having migrated into the 

 lowlands of the coast, has been modified by its new environment. 

 The species has become well enough marked to separate it readily 

 from the upland fallax. It admits, however, of several local races 

 which may some day be christened with varietal names. The ex- 

 treme forms are hopetonensis obsoleta Pils. of Newbern and Wilming- 

 ton, N. Car., a large form entirely without teeth upon the outer lip, 

 and a Yemassee race which is very small and with strongly devel- 

 oped denticles. 



I was surprised to find Euglandina truncata an abundant species 

 so far north. The Yemassee specimens are large, stout fellows of 

 very brilliant pink, rather darker than typical Florida specimens. 



The following is a complete list of my catch, though it cannot be 

 faunally complete. The entire absence of Amnicolids, Unionidx, 

 Vwiparid.se, and of Ancylus is rather striking. I owe many thanks 

 to Dr. Pilsbry for his critical identification of my shells : 



Polygyra thyroides Say. 



Polygyra hopetonensis Strebel. 



