BUI^LETIN 31 



PBLECVPODA. 



Ostrea alabamiensis Lea, Plates 1-5. 



O. gigajttissiina Finch (in part), undescribed, A. J. vS., vcl. 7, 1824, 



P- 39- 

 O. alabamiensis L,ea, Cont. to Geol., p. 91, pi. 3, fig. 71, 1833. 

 O. seinilunata Lea, ibid, p. 90, pi. 3, fig. 69. 

 O. lingula-ianisl^&a, ibid, p. 92, pi. 3, fig. 72. 

 Q. pincerna Lea, ibid, p. 92, pi. 3, fig. 73. 



O. geoi-giana Co., Jr. Acad. Nat. Sci., Phila., 1S34, vol. 7, p. 156. 

 O. contrada Con., Proc. Acad. Nat. Sci. Phil., 1855, p. 269; also Mex. 



ican Boundary Surv. , pi. 18, fig. i. 

 O. alabamiettsis &ndi georgiaiia Qon., Km.]-!:. Conch., vol. i, 1865, p. 



14-15- 

 O. alabamensis de Gregorio, Mon. Faun. Eoc. , 1890, p. 175, pi. 18. 

 O. alabamiensis Cossm., Ann. de Geol., 1893, p. 18. 

 O. claibo7^nensis Q,o\\. MS, Harris, Bull. Am. Pal., vol. i, p. 3, 1895. 

 Ostrea alabamiensis Har., ibid., p. 3. 

 O. alabaniensis and georgi ana (in part) Dall, Tr. Wag. Free Inst. vSci., 



vol. 3, p. 678-683, 1895. 

 ? Ostrea vomer Clark & Martin, Geol. Surv. Md. Eoc, p. 193, pi. i, 19 10. 



Lea's original description. — Shell subelliptical, curved behind, crenu- 

 late on both sides of the beak ; beaks recurved, pointed. 



Diam. . . . Length 2.1, Breadth 1.5 of an inch. 



A single valve only of this species has been received b}' me. The ex- 

 terior of this is roughly squamose. 



The most remarkable character of this species is the fine di- 

 varicate sculpturing of the corneous epidermis. O. prismatica 

 Gray, as described by Reeve from Panama (Conch. Icon. pi. i. 

 fig. i) possesses this feature to some extent. Of the four forms 

 figured and described by I^ea, O. alabamiensis represents most 

 clearly the normal form, hence the name has been retained in 

 preference to the others, although one was described on a previous 

 page. Idea's figure oi alabainie?isis is, however, a little mislead- 

 ing in that it appears to represent a fairly thick shell. The speci- 

 men from which the figure was drawn is thin and pearlaceous. 

 O. semihinafa evidently grew in close proximity to a root, stick, 

 stone or other object and became somewhat distorted. Its pe- 

 culiar shape as figured caused Conrad to refer it to his O. sellis- 

 formis (Am. Jr. Conch., vol. i, p. 15, 1865), a mistake he certainly 



