- 762 - 



which in Si-^eoies of later horizons we fiwi -FijUv nevelO'^p''-'' . 'The 

 chief variations are in o^itline, sons being roimder or higher and 

 shorter than other spe cimens." (jjhll, 1905). 



Ty-oe locality- .- 3ov;clen, Jamaica. 



Reimrks .- Ths small valves of this spe- ' j.re very abuiid- 

 cnt. The nrunoer of radial ribs maj? be as high as twenty- two; the 

 escutcheon is not as deeply impresccd as the Ixmule and the poster- 

 ior dorsal area is more conspicxTOus than the anterior. The degree 

 of inflation is subject to decidea variation. Either the radial 

 or eonoentric sculpture, or "ooth, may be weak. Valves with sup- 

 pressed radials closely approach P. yaguensis . froi.. which they 

 may in general be distingixished by their coarser concentric scuJp- 

 tvve , more pronomicec! -:)osterior dorsal area, more deeply impress- 

 ed lunula, slightly heavier hinge and deeper and coarser inter;aal 

 crenulations ; the typical actinus is, of course, readily distinguish, 

 ed beoaxise of its more prominent radials. ?. actinus is soBller, 

 more rounded and more inflated than P. proteidus, besides having 

 coarser sculpture. 



G u rr e n ce . - 1' o '•'•' Q ^ Iliocene: Sowden beds, Bowden, Jamaica. 

 (Dall, 1905). 



