48a PAL^JONTOLOGY OF NEW-YORK. 



8troplio(l»iita iiiteriiiedia ( n. s.)- 



Platb XCV a. Fiq. 13 & 14. 



Shell semioval. Dorsal valve depressed-convex : hinge-line equalling the 

 greatest width of the shell ; cardinal process duplicate, each branch 

 deeply grooved on the rostral side ; lamelloo thin and curving, and 

 leaving between them and the hinge-line deep pits for the reception of 

 the dental lamellae ; muscular impressions somewhat broadly flabelli- 

 form, and divided by a short low mesial septum. 



BcRFACE marked by fine rounded radiating striae, which are increased by 

 the interstitial addition of very slender sharp striae at intervals be- 

 tween the beak and margin of the shell. Many of the striae curve 

 upwards, and run out upon the hinge-line. 



Fig. 13. The exterior of the dorsal valve. 

 Fig. 14. The interior of the same. 



Oeological position and locality. In the Oriskany sandstone : Cumberland, Md. 



Stropliodonta niaj^nifica. 



Plate XCV A. Fia. 15 - 19. 



For description and references, see pages 414 and 415. 



Fig. 15. A dorsal view, showing the area, which is imperforate and striate. The specimen is 

 below the medium size which this shell usually attains. 



Fig. 16. Ventral view of the same : the margins are broken, and the outline is consequently 

 imperfect. 



Fig. 17. The interior of a ventral valve of the same species, showing a central pit or foramen. 



Fig. 18. View of the area when the linear foramen is closed. 



Fig. 19. Enlargement of the striae, showing their mode of bifurcation, and the puncta which 

 aro very regularly interposed between the strise. 



