124 



[ Senate 



Meganteris elonqatus. 



RhYNCHONELLA ? ALVEATA ( n. S.). 



Pal. N.Y. Vol. iv. 



Shell longitudinally oval or subrhomboidal, much loijger than 

 wide, sloping from near the middle towards the prominent beak 

 at an angle of about 70" : dorsal valve trough-shaped, or having 

 a sinus so large as to involve its entire breadth below the mid- 

 dle ; lateral margins along the upper half curving down, and 

 occupying broad undefined sinuosities on each side of the beak 

 in the cardinal border of the other valve : ventral valve trans- 

 versely arcuate, and almost wholly included in the prominent 

 rounded mesial fold, from which it slopes rather abruptly to 

 the lateral margins ; beak extending beyond the opposite beak, 

 nearly straight. Surface smooth. 



Geological position and locality. Onondaga limestone, 



