BRACHIOPODS. 85 



Spirifera planoconvexus SHUMARD. 



Spirifer planoconvexus Shumard, 1855: Geol. Sur. Missouri, Ann. Rep., 



p. 202. 



Ambocrelin gemmula McChesney, 1860 : Desc. New Pal. Foss.,p. 41. 

 Spirifer planoconvexus Meek & Hayden, 1864: Palse. Upper Missouri, p. 20. 

 Spirifer planoconvexus GeimtZy 1866 : Carb. und Dyas in Nebraska, p. 42, 



tab. iii, figs. 10-18. 

 Martinia planoconvexa McChesney, 1867 : Trans. Chicago Acad. Sci., vol. 



I, p. 34, pi. i, fig. 1. 

 Spirifer planoconvexus Meek, 1S72 : U. S. Geol. Sur. Nebraska, p. 186, 



pi. iv, figs. 4a-b, and pi. viii, tigs. 2a-b. 



Shell quite small, plano-convex, subeircular in outline ; 

 hinge-line somewhat shorter than greatest width of the valves; 

 surface glabrate, with indistinct lines of growth, but under a 

 magnifier often showing minute spines. Ventral valve strongly 

 arched, often with faint traces of a slight median depression ; 

 beak prominent; area of moderate height; foramen narrow. 

 Dorsal valve nearly plane ; beak not well-defined ; area narrow. 



Horizon and localities- Upper Carboniferous, Upper Coal 

 Measures : Kansas City. 



Spiriferina clarksvillensis WINCHKLL. 



Spiriferina clarksvillensis Winchell, 1865: Proc. Acad. Nat. Sci., Phila., 

 p. 119. 



A small form closely resembling S. kentuckenxis, but with 

 longer hinge-line. 



Horizon and localities Lower Carboniferous, Louisiana 

 ( Kmderhook ) limestone : Clarksville ( Pike county ). 



Spiriferina spinosa (NORWOOD & PR ATTKX). 



pirifer spinosa Norwood & Pratten, 1855: Jour. Acad. Nat. Sci., Phila., 



(2), vol. Ill, p. 71, pi. ix, figs. la-d. 



pirifer spinosa Hail, 1858: Geology Iowa, vol I. p. 706, pi. xxvii, figs. 5a-c. 

 Spiriferina spinosa Miller, 1877: Cat. Am. Pal. FOBS., p. 133. 



Larger than 8. kentuckensis, more robust, with shorter hinge 

 line, higher cardinal area, and larger plications. 



Horizon and localities. Lower Carboniferous, Kaskaskia 

 limestone: Ste. Mary ( Ste. Genevieve county). 



