1919.] NATURAL SCIENCES OF PHILADELPHIA. 49 



type comes from off the eastern coast of Florida or from the Baha- 

 mas. These forms are more convex than Stngilla eutykta, more 

 inequilateral, less rounded, and shorter anteriorly, and are sculp- 

 tured posteriorly with a fine zigzag grooving instead of the elongated 

 cone-in-cone of the new species. There is a considerable degree 

 of variation among the recent forms, but the characters hold 

 constant for any one general localit3^ In the shells from off the 

 west coast of Florida the sculpture is approximately uniform over 

 the entire valve. It is possible that even among the recent faunas, 

 the species has not been sufficiently restricted. The species fig- 

 ured on Plate iv, fig. 9, is from Cape Florida, Catalogue Number 

 93380 of the U. S. National Museum Collection. 



Distrihution. — St. Mary^s Formation. 2\ miles northwest of 

 Williamston, Martin County, North Carolina. Duplin Forma- 

 tion. Natural Well, 1| miles north of Magnolia, Duplin County; 

 4 miles north of Lumberton, 2 miles below Lumberton, 4 to 5 

 miles below Lumberton, Fairmont (Ashpole), 1\ miles northeast 

 of Fairmont, Robeson County; Lake Waccamaw, Columbus 

 County, North Carolina. Muldrow's Place, 5 miles southeast 

 of Mayesville, Sumter County, South Carolina. Marks Head 

 Marl. Porter's Landing, Screven County, Georgia. Waccamaw 

 Formation. 4 miles south of Elizabethtow^n on Hammond Creek, 

 and at Walker's Bluff on the Cape Fear River, Bladen County; 

 Neill's Eddy Landing, 3 miles north of Cronley, Columbus County, 

 North Carolina. Caloosahatckie Formation. Caloosahatchie River 

 and Shell Creek, Florida. 



Collections. — U. S. National Museum. Johns Hopkins Uni- 

 versity. The Academy of Natural Sciences of Philadelphia. 



Donax cuneola new species. Plate III, figs. 1, 3. 



General Characters. — Shell small, ventricose, inequilateral, cune- 

 ate. Umbones posterior, opisthogyrate, inflated and fairly con- 

 spicuous for the genus. Anterior margin obliquely truncated. 

 Posterior margin rounded. Base line straight or very slightly 

 contracted in front of the posterior keel which is clearly defined, 

 as a rule, by an elevated ray. Anterior area often feebly differ- 

 entiated by an ill-defined rostrum. 



Sculpture. — Radial sculpture fine and faint, much more con- 

 spicuous in forms from which the periostracum has been eroded. 

 Basal serration sharp. 



Ligaynent. — Ligament short, external, opisthodetic. 

 4 



