EXPLANATION OF PLATE XIX. 



Figs. 1-21. PRODUCTELLA PYXIDATA Hall p. 100 



1-14. Pedicle and brachial views of seven nearly perfect shells. 

 15. View of the interior of a brachial valve. 16-21. Pedicle 

 and lateral views of three very perfect specimens. (W. M., 

 No. 6696.) 



Louisiana limestone, Louisiana, Missouri. 



Figs. 22-34. PRODUCTELLA CONCENTRICA (Hall) p. 98 



22. View of the natural mould of a brachial valve, the holotype. 

 (A. M. N. H., No. 5080-1.) 



Kindcrhook, bed No. 5, Burlington, Iowa. 



23-24. Views of the natural moulds of two brachial valves, en- 

 tirely similar to the holotype. 25-26. Pedicle and lateral views 

 of a nearly complete pedicle valve. 27-28. Similar views of 

 another example. (W. M., No. 9821.) 



Choutcau limestone, Choutcau Springs, Missouri. 

 29-31. Pedicle, brachial and lateral views of a nearly complete 

 specimen. (W. M., No. 6713.) 



Kinderhook, Burlington, Iowa. 



32-34. Pedicle, lateral and posterior views of a nearly perfect pedi- 

 cle valve. (W. M., No. 14769.) 



Kinderhook, bed No. 6, Burlington, Iowa. 



Figs. 35-36. STROPHALOSIA CYMBULA Hall & Clark p. 145 



Pedicle and brachial views of a nearly complete specimen, the 

 holotype. (W. M., No. 11897.) 



New Providence shale, south of Louisville, Ky. 



Figs. 37-38. STROPHALOSIA BEECHERI Rowley p. 146 



Pedicle and brachial views of a nearly perfect pedicle valve, 

 filled with matrix, but showing the cardinal area. The holo- 

 type. (R. R. R.) 



Louisiana limestone, Louisiana, Missouri. 



Figs. 39-41. PRODUCTELLA NUMMULARIS (Winchell) p. 101 



39. View of the exterior of a brachial valve. 40. Internal view 

 of a brachial valve. 41. View of a pedicle valve. Cotypes. (U. 

 M., No. 1340.) 



Chonopectus sandstone, Burlington, Iowa. 



44 



