312 FOSSIL OSTREID^ OF NORTH AMERICA. 



Tbe resemblance of the figures of that species is very great; and if 

 the American oyster does not assume quite the ponderous proportions 

 of its European cousin, the circumstance may be due to local causes, 

 such as crowding. Conrad states that this species reaches a length of 

 22 inches. 



Ostrea viclsburgensis Conrad : 



(Plate LXIII, Figs. 2, 3 ) 

 This species is from the well-known localitj' of Vicksbiirg, Miss. It 

 was published in the Journal of the Philadelphia Academy of Natural 

 Sciences, Vol. I (n. s.), page 126. 



MIOCENE. 



Ostrea ativoodi Gabb. 



(Plate LXVllI, Figs. 4, 5.) 

 This species is said to be either Miocene or Pliocene. It was pub- 

 lished in the Paleontology of California, II, pages 33, 34 ; Plate X, Figs. 

 58, 58a, ; and Plate XI, Fig. 58b. 



Ostrea borealis Lamarck. 



This fossil form is identified with a recent species.* It is published 

 in Lamarck's Animaux sans Vertfebres, second edition VII, page 220. 



There are in the Academy's collections lour specimens of an oyster 

 marked " St. Charles, Maryland, Cope " which answer perfectly to 

 Lamarck's species. It is probably Miocene. 



Ostrea contracta Conrad. 



(Plate LXIX, Figs. 1, 2.) 

 This species is reported by Conrad as coming from Oyster Point, 

 Mexico, and as probably Miocene. It is published in the Eeport of the 

 United States and Mexican Boundary Survey, I, page 160, having been 

 previously ijublished in the Proceedings of the Philadelphia Academy 

 of Natural Sciences, VII, page 269. 



Ostrea disparilis Conrad. 



(Plate LXVI, Fig.s. 1, 2.) 

 From Virginia and South Carolina. Conrad's publication of the 

 species is in his Fossils of the Medial Tertiary Formation, page 51, 

 Plate 26. 



Syi*. — 0. raveneliana Tuomey & Holmes, iu Pliocene Fossils, page 21. 



The differences which were pointed out by Tuomey & Holmes as 

 separating 0. raveneliana from 0. disparilis cannot be said to exist. 



• See Plate LXXX for recent specimens. 



