CRUSTACEA— OSTRACODA. 



367 



posteriorly a strong flange, bearing a single tooth. Cretacic- 

 Recent. 



120. M. consobrina Jones. (Fig. 1668, a-c.) Cretacic. 



Very tumid posteriorly, relatively short ; dorsal and ventral mar- 

 gin nearly parallel ; a faint median sulcus present. 



Bear River formation of southwestern Wyoming. 



Fig. 1668, a-c, Metacypris consobrina (120), dorsal, lateral (left) and posterior 

 view, X 20 ; d-f^ M. subcordata ( 121), dorsal, lateral and posterior view, X 20 ; g, 

 1^, Cytherideris tqualis (122), lateral and dorsal views, X 20 ; i,j, C. impressa (123), 

 I lateral and dorsal views, X 20 ; k, /, Cythere monticula (124), lateral and dorsal 

 I views, X 20 ; w, «, Entomis waldronensis (103), lateral and dorsal views of left valve, 

 [X I- («-A after White ; w, «, after Ulrich. ) 



J 121. M. subcordata Jones. (Fig. 1668, J-/.) Cretacic. 



Larger than preceding ; lateral constriction more anterior ; height 

 [proportionally greater and ventral margin more deeply impressed; 

 [surface pitted. 



Bear River formation of southwestern Wyoming. 



L. Cytherideis Jones. 



Elongate to triangular, with simple hinge; surface smooth, 

 ' pitted or tuberculated. Cretacic-Recent. 



122. C. equalis Jones. (Fig. 1668,^, /?.) Cretacic. 

 Elongate, bean-shaped; valves thinner anteriorly; somewhat 



wedge-like. 



Bear River of Wyoming. 



123. C. impressa Jones. (Fig. 1668, t,;.) Cretacic. 

 Medially constricted by broad ventrolateral constrictions ; ends 



[nearly of equal thickness, narrow and curved. 

 Bear River of Wyoming. 



