134 CARBONIFEROUS AMMONOIDS OF AMERICA. 



POPANOCERAS WALCOTTI White. 



PI. XXII, figs. 9-11. 



1889. Pojxmocf^^ai^ walcotti, C. A. White, Am. Nat., Vol. XXIII, p. 117, PI. I, 



%s. 9-11. 

 1891. Pojyanocenis walcotti., C. A. White, Bull. U. S. Geol. Survey No. 77, p. 'il, 



PI. I, figs. 9-11. 



The following description is quoted from Dr. White's paper: 



Shell di.scoid, periphery rounded; sides gently convex, the inner volutions 

 almost wholly embraced by the next preceding one, and umbilici are consequently 

 minute. Surface marked with numerous slightly raised and slightly sinuous radiat- 

 ing ridges, apparently indicating stages of growth, which extend continuously from 

 one umbilicus to the other across the periphery; septa showing numerous short lobes 

 and saddles, the former [the saddles] being simple and regularh' rounded at the ends 

 and the latter [the lobes] more or less notched or pointed at the extremity. Those 

 near the periphery' have sometimes three digitations. and those near the umbilicus 

 are simple and more or less pointed. 



Tlie specimen liad diameter of about 26 mm. and was entirely septate, 

 hence the body chamber and aperture are unknown. 



Occurrence. — Permian, military crossing of the Big Wichita River, 

 Baylor County, Tex. 



Family CYCLOLOBID^. 



Genus Shumardites Smith, gen. nov. 



The type is Shumardites simondsi, sp. nov. Form subglobose, rather 

 evolute, whorls highly arched, helmet-shaped, deeply embracing. Abdo- 

 men broadly rounded, sloping in a gentle curve to the abrupt umbilical 

 shoulders. Umbilicus broad and deep, exposing the shoulders of the inner 

 whorls. Surface nearly smooth, except for a few obscure constrictions and 

 traces of ribs on the umbilical border. 



Septa complex, divided into numerous lobes and saddles; saddles all 

 rounded and constricted, lobes partly bifid, and becoming slightly ammo- 

 nitic. Ventral lobe divided by a bottle-sha})ed siphonal saddle, the two 

 lobes thus formed being unsynnnetrically divided by a rather deep cleft; 

 first lateral lobe similarly divided; second lateral lobe mucronate and 

 tending to become trifid; third lateral lobe slightly divided; fourth lateral 

 lobe on the umbilical shoulder, narrow and pointed; a fifth lobe stands 

 on the umbilical border. Internal septa complex, consisting of a trifid 



