0. Meyer — Species in the French Old-Tertiary. 151 



AftT. XXIII. — Successional relations of the species in the French 

 Old- Tertiary ; by Otto Meyer, Ph.D. 



In a former article* I have shown that in the American Old- 

 Tertiary formation many species can be traced along through 

 the succeeding strata, and that the similar succeeding forms are 

 apparently connected by descent. In the second part of this 

 article f I said that the same phenomenon is manifest also in 

 the French Old Tertiary formation. The following table may 

 illustrate this. For the principles which have guided me in 

 making out this genealogy, I refer to this Journal, vol. xxix, 

 p. 458. In preparing it I have used only the material in my 

 own collection, and for this reason the table is very incomplete. 

 Naturalists with more material from French localities than I 

 have may complete it and perhaps correct it in some points. 

 In comparisons like these I think it best to avoid the use of 

 descriptions and figures. 



The determinations of the species enumerated in the table 

 were made by Mr. Cossmann, in Paris ; and I have adhered to 

 his determinations, even where I am of different opinion ; in 

 many cases I would not make specific differences where they 

 are made by Deshayes. My purpose here is only to call atten- 

 tion to the fact that evolution is illustrated also by the species 

 of the French Old-Tertiary. Mr. Cossmann is now occupied 

 with a revision of the species of Deshayes. 



LOWER EOCENE. 



1 



2 Ostrea angusta Desk. 



3 Anomia primseva Desh. 



4 Area modioliformis Desh. 

 5 



6, Pectunculus polymorph- 

 I us Desh. 



7 Pectun cuius terebratu- 



laris Lam. 



8 Limopsis lentif or mis 



Desh. 

 9 



10 



11 Cardita planicosta Lam. 



12 Cardita Prevosti Desh. 



13 Cardita imbricata Lam. 

 U 



MIDDLE EOCENE. 



Lamellibranchiata. 

 Ostrea flabellula Lam. 

 Ostrea cyathula Lam. 

 Anomia tenuistriata Desh. 

 Area modioliformis Desh. 

 Area condita Desh 

 Pectunculus pulvinatus 



Lam. 



Limopsis granulata Lam. 



sp. 

 Trigonoccelia deltoidea 



Lam. 

 Nucula Parisiensis Desh. 

 Cardita planicosta Lam. 

 Cardita asperula Desh. 

 Cardita imbricata Lam. 

 Crassatella compressa 



Desh. 



UPPER EOCENE. 



OLIGOCENE. 



Ostrea cubitus Desh. 

 Ostrea cucullaris Lam. 



Area Rigaultiana Desh. 

 Area planicosta Desh. 



Trigonoccelia media Desh, 

 Nucula lunulata Nyst. 



Cardita propinqua Desh. 

 Crassatella rostralis Desh. 



Pectunculus obo- 

 vatus Lam. 



* This Journal, xxix, 457-468, 1885. 



f Ibid, xxx, 66. 



