prominent um"bon:s. The fine Goneentric sciilpture is obsolete 

 or entirely/ absent on most of the specimens at hand, the surface 

 beiiip- smooth except for the often deep, irre"-^"'i'~ '■'I;" ^''■'.sposed siil- 

 (5'i, vhieh may be nresent on any portion of the srirface or alto- 

 gether absent. 



The Recent P. tris'i] oatiis fOonrad) var. blandns Jail (1) is 

 narrower, v;ith prominent, fine regular ooncentrio sculpture; the 



(l). In Dall and Simpson, Bull. U. 3. I?ish Gonna., vol. "0, -ot . 

 1, pp. 493-494, pi. 58, fig. l,'^, 1901. 



Duplin P. t risulcatus (Oonrad) {?.) and its varieties multisirtia- 

 tus (Oonrad) (5) fDuplin) and whitfiel di Dall (4) (Oak Grove, 

 r.iocene and 'Jaccamaw) are distii:g' i.^iB ;;ad by their uiirrower uxiibones. 



(2). Trans. Am. Assoc, li'at . and Geol., vol. 1, p. 110, 1841; 



?os. Ked. Ter. U. 3., p. 71, nl. 40, fig. 5, 1845 (as Lueivig 

 trisulcatus ) . 



(?). Proc. Acad. lat. 3c i., Philadelphia, vol. 1, p. ?07, 1843; 

 70S. lie'., Ter. U. 3., p. 71, pi. 40, fi,-. 6, 1845. 



(4). loc. cit., p. 1370, 1903 ( = ? Lucina tris-'ilcata ..'hitfield. 



Mon. U. S. Geol. Survey, no. 24, p. G4, pi'. IC , ^"'-3. 1-4, 

 1895. 



deeper lunule and coarse concentric sculpture, ^'any of the 



Tampa silex recurrenn are narrovxer than the average Bow den form, whil( 



the Ohipolan specircns reach a larger size. 



