46 



quite -unmistakable. It is, in fact, unique amor^g- the Tertiary and 

 Recent Tuoulas of the Aatillean region and is oo ioiisly so different 

 from the majority of ITuGulas that it might well be referred to a 

 distinct category of more than sectional value. No forms german 

 are Icnov-Ti from the American Tertiaries. Of the re::ent Antillean 

 sr>ecies N. oymell a Dall (l) has regizlar concentric sculpture and 

 smooth internal margins, hut in other features the shell is more 

 typically nuculiform, being less inequilateral and smaller than 

 hilli , roimded- trigonal in outline and having the hinge more sym- 

 metri cal. 



This st^ecies is nan.ed in honor of Mr. Robert T. Hill, Y.^hose 

 reconnaiscance of Jamaica was an important step in the elucidation 

 of the stratigraphic succession of that island. 



Occu-'renoe .- Lower Miocene: Bowden beds, Bowden, Jamaica. 



(1). Bull. Mus . Gompt. Zool., Harvard, vol. 12, pp. 246-247, 



1886; Proc. U.' 3. ''at.Mus., vol. 12, v. 258, pi. 13, fig. 

 1, 1389. 



