EXPLANATIONS OF PLATE 14 (5). 



Pterinea ERISA. page 337 (33). 



Fig. 1. View of the left valve of a specimen of this species partly denuded of the shell. 

 The large quadrangular muscular impression is seen near the posterior 

 wing, the anterior and posterior teeth are also visible. 



Ambonychia acutirostra. page 336 (32). 



Fig. 2. "View of the left valve of a full grown individual. 



Ambonychia aph^a. page 336 (32). 



Fig. 3. View of the left valve, showing impressions of the lateral teeth. 



MoDioLOPsis RECTUS. page 338 (34). 



Fig. 4. The right valve of a small specimen, showing the muscular impressions. 

 '' 5. The left valve of a larger individal, showing muscular impressions and teeth. 



Cypricardinia arata. page 337 (33). 



Fig. 6. View of the right valve of a specimen of this species, natural size. 



MoDioLOPsis DICT.EUS. page 338 (34). 



Fig. 7. View of a cast of the left valve, showing impressions of the lateral teeth. 



Cypricardites ? QUADRILATERA. page 340 (36). 



Fig. 8. A cast of the right valve of the species. 

 ^' 9. View of the anterior slope, showing the filling of the anterior muscular impres- 

 sion near the beak. 

 *' 10. The posterior slope of the valve, showing the lateral teeth and impression of 

 the elevated muscular scar. 



PALiS:oCARDiA coRDiFORMis. page 341 (37). 



Fig. 11. The right side of the cast, showing muscular scar. 

 ^' 12. Posterior profile view of the cast. 



Amphiccelia leidyi. page 339 (35). 



Fig. 13. Cast of a left valve of a small individual. 



'' 14. Cast of the left valve of a large specimen in which there are faint traces of 

 muscular impressions. 



*' 15. Cast of another individual, having a little different proportions and a more per- 

 fect outline. 



