GASTROPODA— BELLEROPHONTIDJE. 



623 



Small, moderately embracing, gradually expanding whorls, with 

 rather abruptly expanding lip ; slit band on flat-topped carina ; 

 revolving striae stronger than transverse. 



Trenton of Kentucky, Lorraine of Ohio 



65. B. leda Hall. (Fig. 837.) Devonic. 

 Aperture rapidly expanding, carina 



rounded ; slit not deep ; revolving striae 

 alternating in size, sometimes fasciculate, 

 principal ones broad and rounded, trans- 

 verse striae fine. 



Hamilton of New York, Ontario, etc. 



66. B. lyra Hall. Devonic. 

 Less ventricose than preceding and with less abruptly expanded 



aperture ; carina elevated and revolving striae equal and firm. 

 Hamilton of New York, Falls of Ohio, etc. 



6j. B. kceneni Clarke. (Fig. 838.) Devonic. 



Fig. 837. Bucanopsis leda. 

 (Copy from Hall.) 



Fig. 838. Bucanopsis kceneni, X 2 - (After Clarke. 



Like B. leda, but smaller, with less rapidly expanding lip and 

 surface strongly tuberculate, through accentuation of ornamenta- 

 tion of B. leda type. 



Portage (Styliolina limestone) of New York. 



68. B. textilis Hall. (Fig. 839.) Mississippic. 



Fig. 839. Bucanopsis textilis. (After Whitfield, Am. Mus. Nat. Hist. Bull.) 



