BBACHIOPODS. 69 



Streptorhynchus occidental Newberry, 1861: ives' Exp. Exped. Colorado 



River, p. 126. 

 Orthisina occidental Swallow, 1863 : Trans. St. Louis Acad. Sci., vol. II, 



p. 83. 

 Orthi* striatocostata Geinitz, 1866: Carb. und Dyas in Nebraska, p. 48, 



tab. iii, figs. 22-24. 

 Meekella striatocostata White & St. John, 1867 : Trans. Chicago Acad. Sci. , 



vol. I, p. 120, figs. 4,5,6. 

 Meekella striatocostata Meek, 1872: U. S. Geol. Sur. Nebraska, p. 175, pi. 



v, figs. ]2a-c. 

 Meekella striatocostala White, 1875: U. S. Geog. Sur. w. lOOMerid., vol. 



IV, p. 126, pi. ix, figs. 4a-c. 



Shell of medium size, subglobose, with from ten to fifteen 

 large radiating plications, which become more or less angular 

 toward the margin ; hinge-line much shorter than the greatest 

 breadth of the valves. Ventral valve somewhat larger than 

 the other ; cardinal area relatively narrow transversely, often 

 higher than wide, and finely lined ; foramen quite narrow, cov- 

 ered by a rounded pseudo-deltidium having a distinct median 

 ridge. The apical portion of the valve is more or less twisted 

 and arched, though occasionally undistorted. Dorsal valve 

 usually less convex than the ventral, often more or less flat- 

 tened centrally and in front; beak incurved, projecting but 

 slightly beyond the hinge-line. Surface of both valves orna- 

 mented by minute 'radiating lines, which anteriorly converge 

 on each side of the several plications. These are crossed by 

 more or less well-defined lines of growth. 



Horizon and localities. Lower Carboniferous, Upper Coal 

 Measures : Kansas City. 



Strophomena deltoidea CONRAD. 



Strophomena deltoidea Conrad, 1839 : Ann. Kept. Geol. New York, p. 64. 

 Strophomena deltoidea Hall, 1867 : Pal. New York, vol. IV, p. 106. 



Eesembling an immature 8. alternata, but with the cardi- 

 nal extremities produced somewhat and the front margin ex- 

 tended. 



Horizon and localities. Lower Silurian, Trenton lime- 

 stone: McCune station (Pike county). 



