PLATE XIX. 



(Figures 1-23 by R. P. Whitfield.) 



Legftnd. j. C:miinal [irocess. a'. Posterior adductors, 



a {=;,'■"). Anterior adductors. v. Bracliial ridges. 



Genus PRODUCTUS, Soweuby. 



(See Plates XVIIa and XVIII.) 

 Page 3-21. 



Productus (Marginifera) splendens, Norwood :uk1 Prattcu (P. lonffispinus, Sowerhy). 



Fiffs. I, 2, 3. Three views of a specimen with a few ribs and scattered spine-bases, and a nacreous shell 

 texture. 



Upper Coal Pleasures. Winttrstt, Iowa. 

 V'\g. 4. The interior of a brachial valve; -showing the cardinal proces.s, mu.scular 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 develoiied here than in any other species observed. The submai-ginal 

 ridges which ch.aracterize Waagen's subgenus M.arginifera are not highly developed in this 

 specimen. X 2. 



Coal Measui'es. La 8alle, I llinois. 



PRODurTus Nebrascensis, Owen {= J\ anpevsH.t. McChe.siiey). 



Figs. 5, 6, 7. Three views of a specimen ; showing the great abundance of short spines. 

 Coal Measures. La Salle, Illinois. 



Productus costatus, Soweiln-. 



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 jiosterior face of tlie cardinal process ; showing its thickened base and trilo- 

 bate character. X 3. 

 Fig. 13. An internal cast of the xieJicle-valve; showing the diductor and ailductoi' muscular scars. 

 Coal Measures. Wlriterset, Iowa. 



Productus punctatus, Martin. 



Fig. 14. The interior of a brachial valve. 



Fig. 15. The cardinal process of the same specimen, viewed tVom the postei-ior side. X 3. 



Fig. 16. The same in profile. X 3. 



Coal 'Measures. Missoui-i. 

 Figs. 17, 18. Two views of a pedicle- valve ; showing the sjnniferous bands which form concentric annulations. 

 Referi-ed 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 mu.scular and 



brachial iinpi'essions. 

 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 diiinctor scai-s. 

 Coal Measures. Itaituba, Brazil. 



