EXPLANATION OF PLATE II. 



Figs. 1-10. LEPT^ENA ANALOGA (Phillips) , p. 49 



1-2. Pedicle and brachial views of a nearly complete specimen. 

 3-4. External and internal views of another smaller pedicle 

 valve. (W. M., No. 4696.) 



Fern Glen formation, near Kimmswick, Missouri. 

 5-6. Internal and external views of a nearly complete brachial valve. 

 (W. M., No. 9719.) 



Chouteau limestone, Pettis County, Missouri. 



7-9. Pedicle, lateral and profile views of a nearly complete but 

 somewhat distorted specimen. (W. M., No. 7055.) 

 Chouteau limestone, Green County, Missouri. 



10. View of the internal cast of a pedicle valve. (W. M., 347.) 



Lower Burlington limestone, near Springfield, Missouri. 



Figs. 11-16. LEPTVENA CONVEXA n. sp p. 52 



11. External view of a brachial valve, and 12, external view of a 

 pedicle valve, in which the geniculate curvature of the shell is 

 wanting. (W. M., No. 13356.) 



Kinderhook, Bed No. 6, Burlington, Iowa. . 



13. Internal cast of a pedicle valve, and 14, the impression of the 

 external surface of a brachial valve. (W. M., No. 6659.) 



Kinderhook, Bed No. 5, Burlington, Iowa. 



15-16. Two views of a pedicle valve in which the geniculation of the 

 shell is absent. (W. M., No. 13357.) 



Kinderhook oolite, Burlington^, Iowa. 



,F,igs. 17-18. STREPTORHYNCHUS ULRICHI Hall & Clarke p. 73 



External and internal views of a pedicle: valve, the holotype. (U. S. 

 N. M., No. 44994.) 



Chester group, 2 miles east of Scottsburg, Kentucky. 



Figs. 19-22. SCHUCHERTELLA cosxATULA (Hall & Clarke) p. 57 



19-20. Brachial and pedicle views of a nearly complete specimen, 

 the holotype. 21-22. External and internal views of an incom- 

 plete pedicle valve, the latter showing the entire absence of a 

 median septum. (W. M., No. 14498.) 



Chester group, Crittenden County, Kentucky. 



