376 FOSSIL OSTREID^ OF NORTH AMERICA. 



PLATE LV. 



ExoGYRA wiNCHELLi White. (Page 307.) 



Fig. 1. — luterior view of the lower valve; natural size. 



2. — Lateral view of the same example. For views of the upper valve see Plate 

 LII. 



ExoGYRA PARASITICA Gabb. (Page 306.) 



3. — Interior view of a lower valve; natural size. 

 4. — Exterior view of an upper valve. After Gabb. 



ExoGYRA COLUMBELLA Meek. (Page 304.) 



5, 6. — Two lateral views of a lower valve ; natural size. 



