GASTEEOPODS. 151 



between his species and the European representative, the pos- 

 session by the former of only sixteen ribs, or about half the 

 number ascribed to B. urii by de Koninck. 



Bellerophon crassus MEEK & WORTHEN. 

 Plate 1, figs. la-b. 



Bellerophon crassus Meek & Worthen, 1860: Proc. Acad. Nat. Sci., Phila., 



p. 458. 

 Bellerophon crassus Meek & Worthen, 1866: Geol. Sur. Illinois, vol. II, p. 



385, pi. xxxi,tigs. 16a-16b. 

 Bellerophon crassus White, 1875: Expl. and Sur. w. 100 merid., vol. IV, 



p. 157, pi. xii, fig. la. 

 Bellerophon crassus White, 1884 : Geol. Sur. Indiana, 13th Ann. Rep., 



p. 157, pi. xxxiii, figs. 1-2. 



Shell very large, massive, subglobose, whorls rather rapidly 

 increasing in size ; umbilicus depressed, but not perforated ; 

 medial band narrow, well defined and bordered on each side 

 by a well-marked ridge. Aperture transversely reniform, or 

 sublunate; outer lip greatly thickened toward the umbilical 

 region, much thinner centrally on each side of the rather narrow 

 sinus ; callosity of the inner labrum thick. Surface unmarked 

 except by lines of growth and irregular wrinkles. 



Horizon and localities. Upper Carboniferous, Upper 

 Coal Measures : Kansas City, Lexington. 



Bellerophon montfortianus NORWOOD & PRATTEN. 



Bellerophon montfortianus Norwood & Pratten, 1855: Jour. Acad. Nat. 



Sci,, Phila , (2), vol. Ill, p. 74, pi. ix, fig. 5. 

 Bellerophon montfortianus Geinitz, 1866: Garb, und Dyas in Nebraska, 



p. 8, tab. i, fig. 13. 

 Bellerophon interlineatus Geinitz, 1866: Carb. und Dyas in Nebraska, p. 9, 



tab. i, fig. 14. (Not Portlock, 1843.) 

 Bellerophon montfortianus Meek, 1872: U. S. Geol. Sur. Nebraska, p. 225, 



pi. ix, fig. 15. 



Bellerophon montfortianus White, 1876: Geol. Uinta Mts., p. 92. 

 Bellerophon montfortianus White, 1882: U. S. Geog. Sur. w. 100 Merid., 



Supp. vol. Ill, app , pp xi, xv and xviii. 

 Bellerophon montfortianus Keyes, 1888: Proc. Acad. Nat. Sci, Phila , p. 



235. 

 Bellerophon montfortianus Keyes, 1889: Proc. Acad. Nat. Sci., Phila., p. 



235. 

 Bellerophon montfortianus Keyes, 1891 : Johns Hopkins Univ. Cir., vol. XI, 



p. 29. 



