LAMELLIBHA.NCHS. 117 



Lithophaga pertenuis MEEK & WOKTHEN. 



Lithophaga ? pertenuis Meek & Worlhen, 1865: Proc. Acad. Nat. Sci., 



Phila., p. 245. 

 Lithophaga? pertenuis Sleek & Worthen, 1875 : Geol. Sur. Illinois, vol. V, 



p. 539, pi. xxii, figs. la-b. 



Much larger and less robust than the species figured; sur- 

 face smooth, with only fine lines of growth. 



Horizon and Localities. Lower Carboniferous, Saint Louis 

 limestone : Saint Louis. 



Myalina keokuk WORTHEN. 



Myalina keokuk Worthen, 3875: Geol. Sur. Illinois, vol. VI, p. 524, pi. 

 xxx, fig. 5. 



Like M. angulata, but with stout beaks and heavier valves . 



Horizon and localities. Lower Carboniferous, Keokuk 



limestone : Bonaparte (Iowa) ; St. Francis ville (Clark county). 



Myalina sancti-ludovici WORTHEN. 



Myalina sancti-ludovici Worthen, 1873 : Geol. Sur. Illinois, vol. V, p. 540, 

 pi. xxii, fig. 3. 



Closely related to M. angulata, but much smaller and more 

 delicate. 



Horizon and localities Lower Carboniferous, Saint Louis 

 limestone : Saint Louis. 



Myalina kansasensis SHUMARD. 



Plate xliii, fig. 5. 



Myalina kansasensis Shumard, 1858: Trans. St. Louis Acad. Sci., vol.1, 

 p. 213. 



Closely related to M. recurvirostris M. & W., but with the 

 concentric lamillse prominently corrugated. 



Horizon and localities. Upper Carboniferous, Upper Coal 

 Measures : Kansas City. 



Myalina recurvirostris MEEK & WORTHEN. 



Plate xlv, figs. la-b. 

 Myahna recurvirostris Meek & Worthen, 1860: Proc. Acad. Nat. Sci., 



Phila., p. 456. 

 Myalina recurvirostris Meek & Worthen, 1866: Geol. Sur. Illinois, vol II, 



p. 344, pi. xxvi, figa.9a-c. 



Myalina recurvirostris White, 1884: Geol. Sur. Indiana, 13th Ann. Kept., 

 pt. ii, p. 140, pi. xxix, figs. 3-4. 



