No. 109.] 



99 



Meganteris ^quiradiata. 



Pal. N.Y. Vol. iii, pi. 45, f. 4. 



Atrypa (equiradiata, Conrad : Jour. Acad. Nat. Sc. Phil., Yol. 8. p. 206; 



pi. 16, f. 17. 



Shfxl elliptical or subovoid ; valves nearly equal ; surface marked 

 by simple regular radiating striae ; beak of the ventral valve 

 moderately incurved, scarcely gibbous ; margins of valves not 

 sinuous. 

 Geological position and locality. Upper Pentaracrus limestone of the 



Lower Helderberg group, Schoharie. 



UgaAMTXSIS .SQUIEXOIXTUS. 



Meganteris LiEvis. 



Pal. N.Y. Vol. iii, pi. 40, f. 2. 



Shell broad oval or subquadrate. not sinuate : ventral valve the 

 more convex, most prominent along the middle and towards the 

 beak, which is pointed and arched so as to rise above the hinge- 

 line, but not closely incurved ; foramen narrow, extending quite 



