174 GA.5STBEOPODS. 



even to the aperture, which is large and sub-circular, or trans- 

 versely oval; lip with its margin all around, excepting on the 

 inner side, undulated so as to form some eight or ten more or 

 less well-defined sinuses, with projecting processes between. 

 Surface marked only by fine undulating lines of growth. 



Horizon and localities. Upper Silurian limestone : Bai- 

 ley landing ( Perry county ). 



As in the case of a considerable number of other shells 

 from the Mississippi basin, it is almost impossible to detect any 

 specific differences between them and the more eastern forms ; 

 and it is very likely that the specimens under consideration 

 will have to be referred to some one of .the New York species 

 described by Hall. 



Capulus haliotoides (MEEK & WORTHBN), 



Plate liii, figs. 9a-b. 

 Ptatyceras haliotoides Meek & Worthen, 1866: Proc. Acad. Nat. Sci., Phila., 



1866, p. 264. 

 Platyceras haliotoides Meek & Worthen, 1868: Geol. Sur. Illinois, vol. Ill, 



p. 458, pi. xiv, figs. 3a-b. 



Capulus haliotoides Keyes, 1889: Proc. Acad. Nat. Sci., Phila., p. 165. 

 Platyostoma broadheadi Miller. 1891 : Geol. Sur. Indiana, 17th Ann. Rep., 

 Adv. sheets, p. 86, pi. xiv, figs. 19-20. 



Shell below medium size, very obliquely ovate, forming 

 one to two very rapidly expanding volutions, which are con- 

 tiguous except near the apertural margin ; whorls compressed, 

 somewhat sharply rounded along the periphery. Spire slightly 

 elevated above the level of the body turn. Aperture ample, 

 oval ; labrum somewhat sinuous. Surface marked by fine un- 

 lating lines of growth. 



Horizon and localities. IJOWQT Carboniferous, . Kinder- 

 hook limestone : Sedalia. 



Capulus paralius (WHITE & WHITFIELD). 



Plate liii, figs. la-d. 

 Platyceras paralium White & Whitfield, 1862 : Proc. Boston Soc. Nat. Hist., 



vol. VIII, p. 302. 



Platyceras paralius Keyes, 1889 : Proc. Acad. Nat. Sci., Phila., p. 294. 

 Capulus paralius Keyes, 1890: American Geologist, vol. VI, p. 9. 

 Capulus paralius Keyes, 1890: Proc. Acad. Nat. Sci., Phila., p. 166, pi. 

 ii, figs. la-b. 



