36 BULIvETiN 31 36 



in the Aldrich Collection. 

 Type. — Lost. 

 Specimens Jigitred. — Paleont. Coll. Cornell Univ^ 



Crenella isocardioides I^ea, PI. 17. Fig-;. 22-24. 



Hippagus isocardioides l^ea., Cont. to Geol.,iS33, p. 72, p. pi. 2, 



fig- 50. 

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



35, figs. 22-28. 

 Crenella 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, L,ength 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 crennlations 

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



7>'/>^.— Phila. Acad. Coll. 



Specimeyis figured . — Paleont. Miis. Cornell Univ. 



Limopsisaviculoides Conrad, PI. iS. Figs. 1-7. 



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

 Pectunculus obliqua Lea, Cont. to Geol., 1833, p. 78, pl. 3, fig. 57. 

 Limopsis aviculoides Con., Jr. Phila., Acad. vol. 5, p. 297, pl. 47, fig. 12. 

 Limopsis obliqua Cossm., Notes Compl., 1893, p. 16. 



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

 minute radiating lines interrupted by regular, prominent, concentric .striae ; 

 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 appears 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 unusuallj' large specimen for Ala- 

 bama in describing the t3'pe. 



