tions 8 short distar.ce from the tip of the "01111)0, which may be 

 smooth ebly iindulated, while the imdula tions down the anter- 



ior slope, if present, are finer than those on ■'■>i'' lov.-den species; 

 in addition ^he umhones are slightly lower, the limiile narrov.'er and 

 the hinge not as be.'"vy. 



"^peci^'ens of this species in ^ai-^n'-'s collections ■-' -^e labell- 

 ed "0_. mar:; land icus Conrad" fl), but that form is obviously differ- 



(1). Dall, v7. H., in Cu^ny and -11, Troc . U. S. Tini-. -^is., vol. 

 19, p. 529, 1896. 



ent. 



OcQ-grrenoe .- lower I.Iiocene : Bov.'den beds, 3ov/den Jamaica 

 (Dall, 1902). 



