LAMBLLIBEANCHS. 123 



Yoldia subscitula ( MEEK & HAYDEN). 



Leda subscitula Meek & Hayden, 1858: Trans. Albany Inst., vol. IV, 



p. 79. 

 Yoldia subscitula Meek & Hayden, 1864: Pal. Upper Missouri, pt. i, p. 60, 



pi. H, figs. 4a-b. 

 Nucula (Leda) subscitula? Geinitz, 1866: Garb, und Dyas in Nebraska, 



p. 22, tab. i, fig. 35. 

 Yoldia subscitula Meek, 1872* U. S. Geol. Sur. Nebraska, p. 205, pi. x, 



fig. 10. 



A small, smooth shell, not unlike a N. bellistriata in gen- 

 eral appearance, bat without the attenuated posterior margin, 

 and with crenate hinge. 



Horizon and localities. Upper Carboniferous, Upper Coal 

 Measures : Kansas City. 



Schizodus wheeleri (SWALLOW). 



Plate xlvi, figs. 3a-c. 

 Cydricardia 'wheeler i Swallow, 1863: Trans. St. Louis Acad.Sci., vol. II, 



p. 96. 

 Schizodus obscurus Geinitz, 1866 : Carb. und Dyas in Nebraska, p. 20, tab. 



i, figs. 30, 31. (Not Sawerby, 1821.) 

 Schizodus wheeleri Meek, 1872: U. S. Geol. Sur. Nebraska, p. 20;), pi. x, 



figs. la-d. 

 Schizodus wheeleri White, 18S4: U. S. Geol. Sur. Indiana, 13th Ann. 



Rep. , pt. ii, p. 147, pi. xxx, figs. 3-5. 



Shell of medium size, longitudinally subovoid, moderately 

 ventricose ; regularly curved in front; narrow and obliquely 

 truncated behind; evenly rounded below; cardinal border 

 straight, inclined slightly backward. Beaks not prominent, 

 situated midway between the anterior and middle of the valves 5 

 posterior umbonal slope rather- well marked by a low rounded, 

 ridge. Surface smooth, marked only by faint lines of growth 



Horizon and local* tier* Upper Carboniferous, Upper Coal 

 Measures: Kansas City. 



Schizodus harii MILLER. 



Plate xlvi, fig. 4. 



Schizodus harii Miller, 1891: Geol. Sur. Indiana, 17th Ann. Rep, Adv. 

 sheets, p. 91, pi. xx, figs. 1-3. 



Larger, shorter and heavier than S. wheeleri. 

 Horizon and localities. Upper Carboniferous, Upper Coal 

 Measures : Kansas City. 



