36 Bui,i,KTiN 31 36 



in the Aldrich Collection. 

 Type. — lyost. 

 Specime7is figured. — Paleont. Coll. Cornell Univ. 



Creneiia isocardioides l^ea, PI. 17. Figs. 22-24. 



Hippagus isocardioides 'Li&sl, Cont. to Geol. ,1833, p. 72, p. pi. 2, 



fig- 50. 

 Hippagus isocardioides de Greg. , Mon. Faun. Eoc. Ala., p. 226, pi. 



35, figs. 22-28. 

 Creneiia isocardioides Dall, Trans. Wag., Ill, '98, p. 803. 



Lea's original description. — Shell cordate, much inflated ; longi- 

 tudinal, minutely and longitudinally ribbed, flattened before and behind, 

 ridged along the umbonal slope ; substance of the shell rather thick ; beaks 

 large, recurved ; cicatrices impressed ; cavity of the shell very deep ; mar- 

 gin minutely crenulate ; nacre somewhat pearly. 



Diam 3-2oths, Length 5-2oths, Breadth 3-2oths of an inch. 



The exterior marking on this minute species is very faint. I 

 have seen none so well preserved that the marginal crenulations 

 show, nor have I seen it elsewhere than at Claiborne. 



7)//^.— Phila. Acad. Coll. 



Specimens figured . — Paleont. Mus. Cornell Univ. 



Limopsisavicuioides Conrad, ■ PI. 18. Figs. 1-7. 



Pechmculns aviculoides Con., Foss. Sh. Tert. Form, Oct., 1833, p. 39. 

 Pectimculus obliqua Lea, Cont. to Geol., 1833, p. 78, pi. 3, fig. 57. '^^<) 

 ....^Linwpsis aviculoides Con., Jr. Phila., Acad, vol.^i^ p. 297, pi. 47, fig. 12.* ^S^i 

 Limopsis obliqua Cossm., 'Notes Cotnpl., iSg^, p. 16. ' 



Conrad's original description. — Shell sub-oval, very oblique, with 

 minute radiating lines interrupted by regular, prominent, concentric stride ; 

 umbo prominent ; beaks rather elevated ; apex acute ; series of cardinal 

 teeth interrupted in the center by a triangular fosset ; cavity capacious, mar- 

 gin crenulated. Length >^ of an inch. 



So far as our knowledge of this species goes it a]:>pears to be 

 mainly confined to the central part of the Mississippi Embay- 

 ment, — Louisiana and Mississippi produce the greater percentage 

 of specimens. The Claibornian specimens are few and compara- 

 tively small. Several years' collection by members of the Geol- 

 ogical Survey of Texas brought to light no specimens. 



Conrad must have had an unusually large specimen for Ala- 

 bama in describing the type. 



