180 PALAEONTOLOGY OF KENTUCKY. 



Macrocheilus carinatus. N. SP. 



Plate XX., figures 20, 21, 22 and 23. 



Shell of medium size, turreted, sub- fusiform ; length less than twice the 

 diameter ; volutions four or five, gradually increasing from the apex, last 

 two ventricose, and the last one occupying one half the length of shell. 



Aperture not known ; indications point to its being elongate. No surface- 

 markings are visible ; they may have been obliterated by the process of silici- 

 fication, to which our specimens were subjected. A peculiarity of this shell 

 is the carina on the periphery of the last volution, as plainly shown in figures 

 20 and 23. It is in fact not a real carina, but produced by the elevation of the 

 lower half of the volution above the surface of the upper half. This species 

 has some resemblance to M. hebe, but differs from it by the peculiar feature of 

 its lower volution. 



Formation and Locality. Found in the Corniferous limestone of the Devonian formation at and 

 around the Falls of the Ohio, in Kentucky and Indiana. 



Genus Polyphemopsis, Poniock. 



Polyp hemop sis, Portlock. Geol. Hep. of Londonderry 1843. 



Etymology: polyphemus, a genus of shells; opsis, appearance having the appearance of Poly- 

 phemus. 



Portlock does not give a definite description of the genus ; but from his 

 article on the subject, the following description may be formulated : 



Shell free, univalve elongated, with a mammillated spire ; mouth narrow ; 

 columella smooth and truncated ; base notched ; the last whorl greater than 

 the balance together ; base of the columella curved ; outer lip is not margin- 

 ated, and does not form on the whorls any suture or varices which might indi- 

 cate the position of former apertures. 



This is the description of Montfort's genus, Polyphemus, from which Port- 

 lock's Polyphemopsis differs by its sharp spire, while Polyphemus has a mam- 

 millated one, and by the want of a wave in outer lip of the aperture. 



Polyphemopsis louisvillae. HALL AND WHITFIELU. 



^Plate XX., figures 16, 17, 18 and 19. 

 Polyphemopsis louismllae, H. and W. 24th Reg. Eep., p. 193 1872. 



Shell small, ventricose, consisting of about six rapidly tapering volutions, 

 the last of which comprises about two-thirds the entire length of shell. Aper- 

 ture large, ovate, widest below the middle, and pointed at the upper angle ; a 

 little more than half as long as the shell. Columella slight ; suture scarcely 

 impressed. 



