158 PALEONTOLOGY OF KENTUCKY. 



be ascertained, or with fine striae or lines of growth, which are often unequally 

 developed on different parts of the shell ; and also with fine longitudinal 

 striae, which may be present with or without the transverse striae. Length 

 different in different individuals. Prof. Hall gives their length from two to 

 five millimeters. 



The specimens before me, which have all the characters mentioned in the 

 foregoing description, are considerably larger ; they are only fragments, with- 

 out apex and aperture, but all indications point at least to a length exceeding 

 half an inch. 



Formation and Locality. Occurs in the upper strata of the Devonian formation, at and around 

 the Fulls of the Ohio, in Kentucky and Indiana. This little shell is rather rare. 



MOLLUSCA. 



GASTEROPODA. 

 Genus Bellerophon. 



Bellerophon, Montfort. Conch. Syst., Vol. 11808. 

 Etymology : a mythological name. 



The type of this genus is Bellerophon bicarinatus. The shells of this genus 

 are symmetrically convoluted, globular or discoidal, strong, few whorled ; the 

 whorls are often sculptured ; dorsally keeled. The apereture is sinuated and 

 deeply notched on the dorsal side ; its shape is variable, sometimes triangular, 

 and sometimes reniform or sub-orbicular. The surface is usually marked by 

 fine concentric striae, and sometimes by fine revolving striae also. 



This genus extends from the Lower Silurian to the Carboniferous, inclu- 

 sively. 



Bellerophon leda. HALL 



Plate XVII., figures 12 and 13. 



Bellerophon leda, Hall. Descpt. of New Sp. of Foss., p. 301861. 

 Bellerophon leda, Hall. Fifteenth Rep. N Y St. Cab., p. 581862. 

 Bellerophon leda, H. and W. 29th Regent's Rep., p. '2001872. 

 Bellerophon leda, H and W. 27th Regent's Rep., pi. 131875. 

 Bellerophon leda'QM. Illust of Dev. Foss., pi 24 1876. 

 Bellerophon leda, Hall. Pal. N. Y , Vol 5, pt. 2 p. 1101879. 



Shell sub-globose, often a little flattened upon the dorstim ; body-whoil 

 ventricose, very rapidly expanding ; aperture very wide ; peristome abruptly 



