No. 109.] 101 



Meganteris ovalis. 



Pal N Y. Vol. iii, pi. 106, f. 2. 



Shell longitudinally oval, compressed , lateral margins subtrnn- 

 cate and abruptly inflected ; front rather narrowly rounded : 

 ventral valve slightly the more elevated, most prominent along 

 the middle, sloping gradually towards the sides ; beak pointed, 

 arched so as to bring the apex above the hinge-line, but not 

 touching the opposite valve, angular along the lateral slopes- : 

 dorsal valve regularly depressed- convex ; beak incurved. Sur- 

 face marked by very feint simple radiating striee, which become 

 obsolete on the upper part. 



Casts and much-worn specimens of this species only have come under 

 my observation. None of these have the apes of the beak entire, nor do 

 they show the character of the foramen. It is evidently very near the last 

 species, but differs, however, in being larger, more compressed, and often 

 proportionally broader. Casts of this species also resemble those of Tere- 

 bratrda ardtiaci of DE Verneuil ( Dunker und VON Meyer, I'alaeon- 

 tologie, dritter band, 4, pi. xxvii, f . 2 ) ; which species, I infer from the 

 reference, is the type of Suess's Genus Meganteris*. 



Geological position and locality. Oriskany sandstone, Hclderberg and 

 Schoharie. 



Meganteris cumberlandi^. 



Pal. N.Y. Vol. iii, pi. 106 a, f. 2. 



Shell oval, ovate or elliptical; valves nearly equal, somewhat 

 acutely rounded in front ; no trace of a sinus in either valve ; 

 lateral margins abruptly inflected : ventral valve rounded and 

 most convex along the middle, sloping laterally and forming a 

 broad semielliptical curve from front to beak, a little more gib- 



* At the time of writing this description, I have seen the name of Meganteris 

 only in a catalogue of the genera given by Davidson in the Annals and Magazine 

 of Natural History for December 1856. 



