Figs. 60-69. ATHYRIS DENSA Hall and Clarke p. 469 



60-63. Pedicle, brachial, lateral and anterior views of a nearly com- 

 plete specimen. 64-65. Exterior and interior views of a nearly 

 perfect pedicle valve. 66-67. Exterior and interior views of 

 another pedicle valve. Cotypes. (W. M., No. 12364.) 



Salem limestone, Colesburgh, Kentucky. 



68-69. External and internal views of a pedicle valve, the holotype 

 of Centronella crassicardinalis White. (A. M. N. H., No. 

 50671.) 



Salem limestone, Spergen Hill, Indiana. 



172 



