122 LAMBLL1BRANCHS. 



Nucula ventricosa Keyes, 1888: Proc. Acad. Nat. Sci., Phila., p. 233. 

 Nucula ventricosa Keyes, 1891: Johns Hopkins Univ. Circulars, vol. XL, 

 p. 29. 



Shell rather small, thick, subovoid, with the greatest 

 breadth slightly in front of the middle ; anterior margin short, 

 straight, or a little concave, rather sharply rounded below ; 

 posterior end but slightly produced, somewhat narrowly 

 rounded ; basal margin broadly and regularly curved. Beaks 

 well denned, and situated a little in front of the middle of the 

 valves. Surface nearly smooth, with a few lines of growth 

 plainly discernible. 



Horizon and localities. Upper Carboniferous, Lower Coal 

 Measures : Clinton ( Henry county ); Upper Coal Measures : 

 Kansas City, Gentry (Gentry county). 



Nuculana bellistriata STEVENS. 



Plate xlv, figs. 4a-b. 



Ledabellistiiata Stevens, 1858: Am. Jour. Sci. ,(2), vol. XXV, p. 261. 

 Leda bellutriata Hall, 1858: Geology Iowa, vol. I, p. 717, pi. xxix, figs. 



6a-d. 

 Nucula kazanensis Geinitz, 1866 : Carb. und Dyas in Nebraska, p. 20, tab. i, 



figs. 33-34 (Not N. kazanensis de Verneuil, 1845.) 

 Nuculana bellistriata, var. attenuata Meek, 1872: U. S. Geol. Sur. Nebraska, 



p. 206, pi. x, figs, lla-b. 

 Nuculana bellistriata White, 1884: Geol. Sur. Indiana, Rep. 1883, p. 146, 



pi. xxxi, figs. 8-9. 



Nuculana bellistriata Keyes, 1888 : Proc. Acad. Nat. Sci., Phil., p. 233. 

 Nuculana bellistriata Keyes. 1891 : Johns Hopkins Univ. Circulars, vol. XI, 



p. 89. 



Shell rather small, subovoid, extended behind ; umbonal 

 regions more or less ventricose, compressed posteriorly, with 

 the umbonal slope quite angular ; regularly rounded below and 

 in front, attenuated behind. Cardinal border in front of the 

 beaks arched ; behind concave, a little elevated or ridged, leav- 

 ing the umbonal slope more or less depressed in the middle. 

 Beaks rather prominent. Surface marked by numerous well- 

 defined concentric thread-like ribs, which are scarcely notice- 

 able after passing the prominent umbonal carina. 



Horizon and localities. Upper Carboniferous, Upper Coal 

 Measures : Gentry ( Gentry county ), Kansas City. 



