PLATE XIX. 
(Figures 1-23 by R. P. Whitfield.) 
Legend, j. Cardinal process. a / . Posterior adductors, 
a (= g). Anterior adductors. v. Brachial ridges. 
Genus PRODUCTUS, Sowerby. 
(See Plates XVIIa and XVIII.) 
Page 321. 
Productus (Marginifera) splendens, Norwood and Pratten (P. longispinus , Sowerby). 
Figs. 1, 2, 3. Three views of a specimen with a few ribs and scattered spine-bases, and a nacreous shell 
texture. 
Upper Coal Measures. Winterset, Iowa. 
Fig. 4. The interior of a brachial valve; showing the cardinal process, muscular impressions and brachial 
ridges. At xx is a row of short spinules which project from the inner surface of the shell, a 
feature more highly developed here than in any other species observed. The submarginal 
ridges which characterize Waagen’s subgenus Marginifera are not highly developed in this 
specimen. X 2. 
Coal Measures. La Salle, 1 llinois. 
Productus Nebrascensis, Owen (= P. aspersus , McChesney). 
Figs. 5, 6, 7. Three views of a specimen ; showing the great abundance of short spines. 
Coal Measures. La Salle, Illinois. 
Productus costatus, Sowerby. 
Fig. 8. The exterior of a pedicle-valve ; showing the general character of the specimens referred to this 
species in this country. 
Figs. 9, 10. Profiles of two individuals of different size. 
Fig. 11. The interior of a brachial valve, with the muscular impressions and brachial ridges. 
Fig. 12. An enlargement of the posterior face of the cardinal process; showing its thickened base and trilo¬ 
bate character. X 3. 
Fig. 13. An internal cast of the pedicle-valve; showing the diductor and adductor muscular scars. 
Coal Measures. Winterset, Ioiua. 
Productus punctatus, Martin. 
Fig. 14. The interior of a brachial valve. 
Fig. 15. The cardinal process of the same specimen, viewed from the posterior side. X 3. 
Fig. 16. The same in profile. X 3. 
Coal ‘Measures. Missouri. 
Figs. 17, 18. Two views of a pedicle-valve ; showing the spiniferous bands which form concentric annulations. 
Referred to this species with doubt. 
Coal Measures. Locality ? 
Productus semireticulatus, Martin. 
Fig. 19. The central portion of a brachial valve, which retains with unusual distinctness the muscular and 
brachial impressions. 
Fig. 20. Posterior view of the cardinal process ; showing the complete coalescence of the inner divisions of 
the two lateral lobes. X 3. 
Fig. 21. The inner face of the same. X 3. 
Fig. 22. The interior of a small brachial valve. 
Fig. 23. The interior of a pedicle-valve ; showing the adductor and diductor scars. 
Coal Measures. Itaituba, Brazil. 
