FREE INSTITUTE OF SCIENCE 



843 



TERTIARY FAUNA OF FLORIDA 



Corbula (Cuneocorbula) Gregorioi Cossmann. 

 Corbula coniprcssa \ar. Gregorioi Cossm., Ann, Geol. et Pal., 12, p. 6, pi. i, figs. 4, 5, 



1894. 

 Corbula Aldrichi \'ar. smithvillcnsis Harris, Proc. Acad. Nat. Sci. Phila. for 1895, p. 52, 

 pi. 3, fig. 5<?, 1895. 



Eocene of Prairie Creel-; and Coffeeville, Alabama; of Newton and Wah- 

 tubbee and Clarke Count)', Mis.sis.sippi ; of Meridian and Claiborne, Alabama ; 

 Mount Lebanon and Montgomery, Louisiana; Lee County, Texas ; the Gatun 

 beds of the Isthmus of Darien, and in the Jacksonian of Clarke County, 

 Mississippi. 



This small and rather variable form seems to me specifically distinct from 

 either of the species to which it has been referred as a variety. 



Corbula (Aloidis) oniscus Conrad. 

 Corbula oniscus Conr., Am. Journ. Sci., x.xiii., p. 341, Jan., 1833 ; and same, N. S., i., p. 



219, pi. 4, fig. 13, 1846. 

 Corbula Murchisoiiii Lea, Contr. Geol., p. 46, pi. i, fig. 13, Dec, 1833 ; Gregorio, Mon. 



Claib., p. 231, pi. 37, figs. 22-39, P'- 38, figs. 1-13, 1890. 

 Corbula gibbosa Conr., Am. Jonrn. Conch., i, p. 3, 1865 ; not of Lea. 

 Corbula ritgosa Heilprin, Proc. Acad. Nat. Sci. Phila. for 1890, p. 401 ; not of Lamarck. 

 Corbula CAurchisonii Gre^ono, Mon. Claib., p. 233, 1890. 

 Corbula (^Neard) ignota Gregorio, op. cif., p. 232, pi. 37, figs. 15-18, 1890 (smooth 



valve). 

 Corbula nasuta Gregorio, op. cit., p. 232 (in synonymy, not of Conrad, 1S33). 



Eocene of the Chickasawan stage at Wood's Bluff, Alabama; of the 

 Claibornian at Claiborne and Clarksville, Alabama ; and of the Jacksonian at 

 Jackson, Mississippi. 



This species is subject to a scaling off of the outer sculptured layer of 

 the shell, leaving the latter in an apparently perfect condition, nearly smooth, 

 and with sundry s-ulci on the dorsal side of the rostrum which do not appear 

 on the uninjured shell. In this state it has every aspect of a distinct species. 

 The left valve has apparently been described by de Gregorio as a distinct 

 species, the sculpture and form being quite different from that of the right 

 valve. 



This species belongs to a group of closely related forms which appear to 

 be distinct, though the characters might be regarded at first as varietal. They 

 appear in different horizons, and they do not seem to grade into one another, 

 so I have regarded them as species. 



