160 PALAEONTOLOGY OF KENTUCKY. 



Bucania devonica. HALL AND WHITFIELD. 



Plate XXVI., figure 9, and Plate XXII., figures 3 and 4. 

 Bucania devonica, H. and W. 24th Regent's Kep., p. 195 1872. 

 Bucania devonica, H. and W. 27th Kegent's Rep., pi. 13 1875. 



Shell discoid, widely and equally umbilicate on the two sides ; remaining 

 volutions about four ; slightly embracing, vertically compressed, giving the 

 transverse diameter a little more than twice the vertical diameter. Lateral 

 margins of the volutions obtusely angular towards the dorsal side. 



The surface has apparently been marked by several (three or four) revolving 

 ridges or carina on each side of the center or dorsum, which is greatly concave. 

 Finer surf ace- markings, and also the form and size of tjie aperture, are un- 

 known. 



Formation and Locality. Occurs in the Corniferous rock of the Devonian formation in Jefferson 

 county, Ky., and in Clark county, Ind. It is always found in an exfoliated condition as internal casts, 

 which seldom show any surface-markings at all, 



Genus Platyceras. conrad, 



Plaiyceras, Conrad. Ann. Geol. Rep. of N. Y. 1840. 



Etymology ; platys, broad ; keras, a horn. 



Copied from Hall's Pal. N. Y,, Vol. 3, page 3091859. 



Shell depressed sub-globose, sub ovoid or obliquely sub-conical. Spire small, 

 volutions few, sometimes free and sometimes contiguous, without columella. 

 Aperture more or less expanded, often companulate, and sometimes with the 

 lip reflected. Peristome entire or sinuous. 



Surface striated or cancellated, often spirally ridged or plicated, and some- 

 times strongly lamellose transversely, nodose or spiniferous. 



Platyceras bucculentum. HALL. 



Plate XXIII., figures 9 and 11, and Plate XXV,, figure 8. 

 Platyceras bucculentum. Hall. Desc, of New Sp of Foss , p. 6 1861. 

 Platyceras bucculentum, Hall 15th Regent's Rep, p. 33 1862. 

 Platyceras bucculentum, Hall, lllust of Dev. Fossils, pi. 3 1876. v 



Platyceras bucculentum, Hall. Pal. N. Y., Vol. 6, pt. 2, p. 101885. 



Shell ventricose, obliquely sub-ovoid ; apex extremely attenuate, the spire 

 making one or two closely enrolled volutions, with a gently enlarging diameter, 

 and below this abruptly expanding; very ventricose in the middle and lower 

 part, spreading more upon the right side than upon the left. The shell near 

 the posterior side swells out into a distinct pouch-like projection, with two or 

 three rounded folds or semi-plications, which give a deeply sinuous outline to 

 the margin. Aperture sub- ovate and sinuate on the right posterior side. Per- 



