TRANSACTIONS OF WAGNER 

 1528 



TERTIARY FAUNA OF FLORIDA 



in his monograph of the Claiborne fauna. It is an internal cast and has not 

 much the aspect of a Thracia. It has, however, concentric ripples, and may 

 represent a tendency towards Cyathodonta on the part of some Eocene form. 



Family PERIPLOMATID^. 



Genus PERIPL.OMA Schumacher. 

 Corbula (sp.) Bruguiere, Encycl. Meth., livr, ii., pi. ccxxx., figs. 6a-6b, 1797. 

 Periploma Schumacher, Essai, p. 115, 1817, type P. incequivalvis Schwm., ^ Anatina 



trapezoides Lam. ; Rang, Man., p. 325, 1829. 

 Osteodesma A, Blainville, Man. de Mai., ii., p. 660, 1827; A. trapezoides Lam. 



Subgenus COCHLODESMA Couthouy. 

 Ligula (sp.) Montagu, Test. Brit. Suppl., p. 96, 1808 (Mya pratemiis Pult.) ; Brown, 



111. Conch. Gt. Brit., expl. pi. xiv., figs, i, 2, 1827 ; Zool. Textb. i., p. 461, 1832 ; III. 



Conch. Gt. Brit., ed. ii., p. 106, 1844; not Ligula Bloch, Vermes, 1781. 

 Cochlodesma Couthouy, Boston Journ. Nat. Hist., ii., p. 170, 1839, type Anatina Leana 



Conrad; Gray, Ann. Mag. N. Hist., ii., p. 25, 1840. 

 Bontcea (Leach MS.) Brown, III. Conch. Gt. Brit., 2d ed., p. 106, 1844; in synonymy of 



Ligula prcetcnuis Brown; Gray, List. British An., Moll., p. 70, 1851. 

 Bontia Gray, P. Z. S., 1847, p. 190; Herrmannsen, Ind. Gen. Mai., Suppl., p. 17, 1852. 

 Galaxura Leach, Moll. Gt. Brit., p. 271, 1852; Mya pratenuis Pult. 

 fCalcarcea Recluz, Act. Soc. Lin. de Bordeaux, xxvii., p. 47, 1869; not Calcarius Bechst., 



1802. 



Osteodesma (Deshayes MS.) Blainville, included several incongruous 

 forms, but Blainville mentions as the type Anatina myalis Lam., which is a 

 typical Thracia, and therefore the name cannot be conserved. 



The genus and its subdivisions show a gradual modification of the hinge- 

 characters. In Periploma there is a strong, prominent clavicular rib support- 

 ing the chondrophore, and in front of the latter is a small, lunate lithodesma ; 

 in Cochlodesma the clavicle is obsolescent and in front of the chondrophores 

 there is a cartilaginous mass of dark-brown color, uniting the valves and 

 occupying the place of the lithodesma, but uncalcified. In the European form, 

 Bontcea, the clavicle is non-e.xistent, but a minute lithodesma still remains. 



Periploma OoUardi Harris. 

 Periploma Collardi Harris, Proc. Acad. Nat. Sci. Phila. for 1895, p. 52, pi. iii., fig. 4. 

 fAnatina claihornensis Lea, Contr. Geol., p. 40, pi. i., fig. 8, 1833. 



?Periploma claibornensis Conrad, Am. Journ. Conch., i., p. 3, 1865 ; Checkl. Eocene Fos. 

 N. Am., p. 34, 1866. 



