- 517 - 



DO! 'AX OYT/IOBIA n. sp. 



Description .- Shell small, elongate sulDelliptical, moderate- 

 ly inequilateral, niod eratel:: inflate'; roiTndsrl anteriorly and 

 posterijrl^, , iie f.nccrior cn;i nore at cenuaued ; unioo lev/, stro.ir- 

 Iv opistho-yrate, situated behind the nieclian vertical; external 

 sciil"otiH'e of fine, rcpr-al?.r, impresse'"'' concentric strie.c, "becom- 

 ing e:;owded tov/ard tne ui::bo, \7i th prominent narro.. radials on 

 the posterior end, the rsdia,ls hecomins' weaker over the middle 

 of the shell and obsolete anteriorly;; left vrlve r.lth a TDromi- 

 nent prosodetic resiliary groove, follov.ed, posteriorly^ b- the 

 cardinals, the oosterior small, compresse '. , its axis almost at 

 right angles to that of the anterior; ri~ht vrlve '.vith t?;o c: - 

 inals; on both valves the hime plate na-To.v, ^ne laterals relat- 

 ively distant and strong; inner margin of the posterior end of the 

 shell wea^cly crenulatel; pallial sinvis mor' ly rleep, roiuided. 



Pi ..erisions .- Length, 6 ram.; alt., 4...' :.iz:.t ; Ljcnidiam., £ mm* 

 RemarL'S .- Several vr-lves of this beautifully scu] nture''. 

 species are at hand. It has a more modern arjp?ct than the rroup 



to v/hich lemioi^ii oeloriTS and can not be co^iiuDe.i v/ith that 

 soecies. The posterior radials are subangular, separated by 

 narroT/cr inters-oaces and nodulated b- the overridinr concentric 

 sculpture . 



Occurreii-e.- Iov;er Miocene: Bov/den beds , Borden, Jamaica. 



