TRANSACTIONS OF WAGNER 

 1 142 



TERTIARY FAUNA OF FLORIDA 



Lepton, which is closely related to Erycina, is distinguished from it by the 

 greater concentration of the dentition, which is usually lower down in the 

 valve from the dorsal margin, by the much shorter and straighter lateral 

 laminae, the valves flattened by compression and more equilateral and quadrate 

 in outline, and by the greater extension of the mantle-edge over the outside of 

 the shell. 



Subgenus Scacchia Philippi. Type Tellina elliptica Scacchi. 



One right and two left cardinals ; laminae obsolete ; external ligament small 

 but distinct ; pallial line simple ; foot compressed. 



The left anterior tooth may be a concentrated lamina and not a cardinal. 

 In the right valve the dorsal margins are extended, as if to take the place of 

 lamina, functioning, in connection with the dorsal margins of the opposite 

 valve, like the grooves in Erycina. S. tenera Jeffreys has only one cardinal in 

 each valve. This group appears to be represented by a fragment of a hinge 

 from the Chipola beds. 



Subgenus Aiioiiialokellia Cossmann. Type Erycina catalauncnsis Cossm., Cat. 

 Illus., ii., pp. 75-76, pi. iii., figs. 29-31, 1887. 



Hinge with two left and one right cardinal, the posterior laminje developed, 

 the anterior wanting, the resilium small, leaving a feeble pit behind the car- 

 dinals. Otherwise as in Erycina. 



Only one species is known, a fossil of the Parisian Eocene. 



Subgenus Pscudopythina Fischer, 1884. Type Kellia MacAndrczvi Fischer, 

 J. de Conch., xv., p. 194, pi. 9, fig. i, 1867. 



Shell rather large for the family, reniform, with a coarse rugose peri- 

 ostracum; hinge with two projections of the right dorsal margin fitting into 

 sulci of the opposite valve, one right and one left cardinal, a strong internal 

 resilium, sometimes with a lithodesma, and an evident but small external liga- 

 ment ; laminae absent or not distinct. 



The nude name without means of identification appeared in a list published 

 by Fischer in 1878. I have not found it characterized earlier than 1887, but 

 it was identified with its type by Monterosato (Nom. Conch. Medit., p. 17) 

 in 1884. It is probably commensal with Crustacea. 



PSubgenus Tiirquetia Velain, Comptes Rendus, July 24, 1876; Faun. St. Paul 

 et Amst., p. 134, 1878. Type T. fragilis Velain, op. cit., p. 135, pi. 5, 

 figs. 15-17, 1878. 



