7-71 - 



ally olDSCuxe radial impressions on the anterior slope, and the 

 right anterior lateral stroi\v-er. It should he noted that the 

 angle between the posterior dorsal margin and the lateral margin 

 on the single adxilt valve a' hand is more rounded than on most cuad- 

 ri sulcata ; t^'pica^ly ouadris'^iloata has thf-> nor sal angles suhaagii- 

 lar, while on chi'oolana the;y" are rounded, hut these features are 

 not constant. 



Oocurrenee «- Lower Miocene : 7o'-':l:n beds. Bow den, Janaica. 

 Ivliocene: Oalvert forrmtion, Virginia (auotores), ?Maryland (Dall, 

 1905; Glenn, 1904): St. Hary's '^o-'^o :- ion, Virginia (Gardner, Mss.), 

 north Carolina (Gardner, Kss.); Yorktown formation, Virginia 

 (auotores), "orth Carolina (Gardner, IIss. ) ; Duplin formation 

 Z'orth Carolina (auctoros ), 3o^^th Carolina (Gardner, Mss.); 

 Choctawhatchie marl, Florida (Dall, 1905). Pliocene: V/acca- 



maw formation, Forth Carolina (Gardner,. IIss.), South Carolina, 

 (Gardner, IIss.); Santa I'aria, Tatetla, Vera Cruz, I'erico (Bose, 

 1906). Pleistocene: Simmons bluff. South Carolina (Dall, 1905). 

 I^ecent: llahant. Has sac hus setts southward through the V/est Indies 

 to o5n':a Caterina, Brazil in both she^ l^^- ^r' ^ "eep water. 



