532 



NORTH AMERICAN INDEX FOSSILS. 



468. L. meeki White. (Fig. 722.) Cretacic. 



Surface marked with radiating striae and fine concentric growth 

 lines. 



Coloradoan : Utah. 



Fig. 723. Cymella bella 

 J. Pal., I.) 



Fig. 722. Liopistha meeki, cardinal and right views. (After Stanton.) 



469. L. (Cymella) bella (Conrad). (Fig. 723.) Cretacic. 



Radiating ribs strongest on middle of valve. 



' Ripleyan of New Jersey (Cliffwood- 

 Wenonah), Virginia and Gulf region. 



470. L. protexta (Conrad). Cretacic. 

 A concave area at posterior extrem- 

 ity nearly or wholly destitute of ribs. 



Ripleyan of New Jersey (Wenonah— 

 Tinton), Gulf region. 



471. L. (Cymella) undata Meek and 

 (N. Hayden. Cretacic. 



Radii finer than in L. bella. Type 

 of subgenus Cymella. 

 Montanan : throughout the Rocky Mountain region ; Wenonah 

 of New Jersey. 



CXXX. Cuspidaria Meek. 



Hinge without teeth, but with a small, internal, posteriorly in- 

 clined resilifer in each valve and an elongated ridge behind it. 

 Ligament subinternal, anterior to the beaks or obsolete. Pallial 

 line simple. Surface concentrically sculptured. Jurassic-Recent. 



472. C. ventricosa Meek and Hayden. Cretacic. 

 Posterior side of shell the longer, usually abruptly contracted. 



Surface marked with concentric striae. 



Ripleyan of New Jersey (Wenonah-Tinton), Montanan of South 

 Dakota and Montana. 



473. C. moreauensis Meek and Hayden. (Necerantoreauensis.) 



Cretacic. 



