PLATE XIX. 



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



Legend, j. Cardinal process. a'. Poslenoi- adductors. 



. a(=g). Antei'ior adductors. v. Bi-ac;liial ridges. 



Genus PRODUCTUS, Sowekbv. 



(See Plates XVIIa and XVIII.) 

 Page 321. 



Productus (Marginifera) splendens, Norwood and Pratteu (P. longispinus, Sowerhy). 



Figs. 1, 2, 3. Thi'ee views of a specimen with a few ribs and scattered spine-bases, and a nacreous shell 

 texture. 



Upi:)ei- Coal Measures. Wintersct, Iowa. 

 Fig. 4. The interior of a bi'achial valve; showing the cai-dinal pi-oces.s, muscular impressions and brachial 

 ridges. At ara; is a row of shoi't spinules whicVi project from the inner surface of the shell, a 

 feature more highly developed here than in any other species observed. The submarginal 

 ridges which charactei'ize Waagen'.s subgenus M.\rginifera are not highly developed in this 

 specimen. X 2. 



Coal Measures. La Salle, 1 llinois. 



Productus Nebrascensis, Owen (= P. aspersus, McChe.suey). 



Pigs. 5, 6, 7. Three views of a specimen ; showing the gi'eat abundance of short spines. 

 Coal Measures. La Salle, Illinois. 



Productus costatus, Soweihy. 



Fig. 8. The extei-ior of a pedicle-valve ; showing the general character of the specimens I'eferred to this 



species in this counti'y. 

 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 oast of the pedicle-valve ; showing the diductor and adductor muscular scare. 

 Coal Measures. Winterset, Iowa. 



Productus punctatus, Martin. 



Fig. 14. The interior of a brachial valve. 



Fig. 15. The cardinal process of the same specimen, viewed fi'om 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 Measui-es. 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. 



