164 PROCEEDINGS OF THE ACADEMY OF [1890. 



coiled than in that species and the body whorl is much more ex- 

 panded. 



Capulus ■? piso (Walcott). 



Plalyccras piso Walcott, 1884. False. Eureka Dist., p. 254, pi. xxiv, figs. 7, 

 7a, 7b. 



Shell below medium size, composed of about two loosely-coiled 

 volutions, gradually expanding ; body-whorl broadly rounded and, 

 for the most part, free from the spire, which is rather small ; several 

 small obscure longitudinal folds are discernible toward the aper- 

 ture. The latter is subcircular or subovate ; lip sinuous. Surface 

 exhibiting only numerous fine lines of growth. 



Horizon and locality. Lower Carbonic : Eureka District, Nevada. 



There is some doubt as to the correct generic reference of this spe- 

 cies. The shell appears to differ in several important particulars 

 from Capulus and it is not improbable that eventually this form will 

 be placed elsewhere. 



Capulus formosus (Keyes). [Plate 11, fig. 8.] 



Platvceras fonnosum Keyes, 1888. Proc. Am. Philosophical SciC, vol. xxv, p. 

 242, figs. 8 and 9. Reprint, p. 14. 



Capulus foj-mosiis Keyes, 1890. Am. Geol., vol. V. 



Shell arcuate, slightly oblique, enlarging rather rapidly to the 

 ample, irregularly pentalobate aperture; posterior side rather short 

 and concave ; lateral slopes nearly straight. Apex obtuse. Surface 

 marked by five broad well-defined longitudinal plications, each of 

 which is composed of several smaller folds ; these are crossed by sin- 

 uous lines of growth. 



Horizon and locality Kinderhook beds : Marshall county, Iowa. 



The two specimens of this species found are both attached to the 

 vaults of specimens of Dorycrinus immaturus W. & Spr. described 

 in the eighth volume of the Illinois Geological Survey. This spe- 

 cies resembles, in some respects, C. paralius (W. & W.) but is sim- 

 ply arcuate instead of being coiled. 

 Capulus cornuformis (Winchell). [Plate II, fig. 5.] 



Platyceras conutforme A. Winchell, 1863. Proc. Acad. Nat. Sci., Phila., 1863, 

 p. 18. 



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



Shell small, arcuate, forming about half a volution, rapidly ex- 

 panding ; young specimens often broadly and obtusely subcarinate 

 along the dorsum. Aperture irregularly oval or subcircular ; mar- 

 gin sinuous. Surface glabrate ; lines of growth scarcely discernible. 



