216 PROCEEDINGS OF THE ACADEMY OP 



DESCRIPTIONS OF A NEW RECENT SPECIES OF GLYCIMERIS, FROM 

 BEAUFORT, NORTH CAROLINA, AND OF MIOCENE SHELLS OF NORTH 

 CAROLINA. 



BY T. A. CONRAD. 



GLYCIMERIS, Klein. II. and A. Adams. 



G. bitruncata. PL 7, fig. 1. Short, rhomboidal, ventricose, 

 contracted, and obliquely truncated anteriorly ; posterior margin 

 oblique, slightly emarginate, cardinal tooth in right valve small, 

 compressed, flattened on the posterior side; pallial sinus widely 

 and obtusely rounded. 



Locality. Fort Macon, N. C. A. C. Beals, U. S. A. 



This interesting shell was sent to the Academy by Dr. Yarrow, 

 from Fort Macon. I suppose it to be a recent shell, on account 

 of its polish, and part of the unaltered ligament remaining. Two 

 specimens were found. It is the only recent species of Glycimeris 

 inhabiting the coasts of North America. There are five species 

 in the Miocene of Virginia and North Carolina. The genus 

 Panopcea is only represented in North America by P. arctica, 

 Lam., which inhabits the Banks of Newfoundland. 



DONAX, Lam. 



D. idoneus. PL T, fig- 2. Shell triangular, elongated, ventri- 

 cose on the posterior side; anterior side flattened, cuneiform, 

 rounded at the extremity ; posterior side acutely rounded at the 

 end, margin very oblique, concave, disk radiated with impressed 



lines. 



Locality. Coast of North Carolina, probably from a Miocene- 

 bed under the sea. It was found by Dr. Yarrow, TJ. S. A. 



0STREN0MIA. Conrad. 



Shell inequivalved, irregular, substance laminated as in Ostrea, 

 hinge with a triangular cartilage pit; right valve with a deep 

 notch or sinus having an internal raised margin ; left valve with 

 an angular bifurcating dentiform process at the base of the carti- 

 lage pit; muscular impression one in each valve. 



0. Carolinensis. PL 7, fig. 3. From the Eocene of North 

 Carolina, where it was found by Prof. Kerr, State Geologist. 



Prof. Morse has shown that A nomia ephippium is a rover in 

 the first stage of existence, then fixed by a byssus which issues 



