EXPLANATION OF PLATE LXXVIII. 



Figs. 1-5. ATHYRIS LAMELLOSA (Leveille) p. 465 



1. Pedicle view of a nearly complete specimen. (W. M., No. 7605.) 



Keokuk limestone, Warsaw, Illinois. 



2. Pedicle view of a nearly complete internal cast. (W. M., No. 



14224.) 



Residual chert, Cooper County, Missouri. 



3-4. Pedicle and posterior views of a nearly complete internal cast. 

 (W. M., No. 7599.) 



Burlington chert, Louisiana, Missouri. 



Figs. 6-9. ATHYRIS PAPILIONIFORMIS McChesney p. 468 



Pedicle, brachial, lateral and posterior views of a sulphur cast of 

 the holotype. (W. M., No. 13232.) 



Chester Group, Fountain Bluff, Illinois. 



Figs. 10-14. ATHYRIS HANNIBALENSIS (Swallow) p. 467 



10-12. Lateral, brachial and anterior views of a nearly complete 

 specimen. 13-14. Pedicle and posterior views of another speci- 

 men. (W. M., No. 6690.) 



Louisiana limestone, Louisiana, Missouri. 



Figs. 15-20. ATHYRIS LAMELLOSA (Leveille) p. 465 



15-16. Views of two pedicle valves upon one of which the lamellar 

 extensions of the shell are well preserved. (W. M., No. 13539.) 



Fern Glen formation, Fern Glen, Missouri. 



17-20. Brachial, pedicle, lateral and anterior views of an exfoliated 

 specimen. (W. M., No. 8545.) 



Pierson limestone, near Springfield, Missouri. 



Figs. 21-24. CLIOTHYRIDINA GLENPARKENSIS n. sp p. 473 



21-22. Pedicle and lateral views of a nearly complete specimen. 

 23-24. Brachial and posterior views of another specimen. (W. 

 M., No. 13901.) 



Fern Glen -formation, Fern Glen, Missouri. 



Fig. 25. CLIOTHYRIDINA PARVIROSTRA (Meek and Worthen) p. 481 



View of the internal cast of a pedicle valve. (W. M., No. 383.) 

 Residual chert, Springfield, Missouri. 



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