PLATE III. 



Page 

 OSTREA TECTICOSTA Gabb 'Si 



Fig. 1. Exterior of the type specimen. 

 2. Interior of the same. 



OsTREA LARVA var. XA8UTA Morton M 



Fig. 3. A speciaieu showing more than the nsual number of plications. 

 4. Another iudivicUial with few plications. 



OsTKEA LARVA Lamarck 34 



Fig. 5. Eigbt side of a specimen of the usual character. 



6. Opjiosite side of the same. 



7. Interior of a specimen showing very many plications. 



OsTREA PENTICULIFERA Conrad 29 



Fig. 8. Exterior of a specimen identified and labeleil by Mr. Conrad, from Haddontield, N. J. 

 9. Interior of the same. 



OSTREA CKENULIMARGINATA Gabb 30 



Fig. 10. Exterior view of a single valve from Marlborough, N. J. 

 11. Interior view of the same. 

 OsTREA PLUMOSA Morton 31 



Fig. 12. View of Dr. Morton's type specimen. 

 13. View of a more elongate specimen. 



OSTREA SUBSPATULATA f Lyell 32 



Fig. 14. View of a cast which is doubtfully referred to this species. 

 Gryph^ea vesicularis Lamarck 36 



Fig. 15. Exterior view of a specimen of the form described by Dr. Morton as G. convcxa. 

 l(j. View of the upper side of a smaller form without the lateral extension. See Plate 

 III, Fig. 2. 



274 



