Io6 PALEONTOLOGY OF KENTUCKY. 



Surface marked by fine concentric lines of growth, which are often crowded 

 into prominent wrinkles towards the front. Shell structure finely punctate. 



The interior shows a short terebratuliform loop, which is abruptly recurved 

 at its lower extremities. 



This species resembles Ter. lincklaeni, from which it differs, however, by its 

 greater gibbosity, by having its greatest width above the middle, while that 

 species has its maximum width near the base, and by its truncated or sinuate 

 base. 



Formation and Locality. Pound in the rotten hornstone of the Devonian formation in Jefferson 

 county, Ky., and in Clark county, lud, A rather rare species. 



MOLLUSCA. 



PTEROPODA. 

 Genus Tentaculites. 



^ Tentaculites, Schiotheim. Petrefacten 1820. 

 Etymology : tentaculum, a feeler ; lithos, stone. ] 



The shells belonging to this genus are easily distinguished by their exterior 

 appearance ; they form very elongated, slender cones, marked by prominent 

 annulations and fine transverse striae. 



The place which these shells had to occupy in the great sub-kingdom Mol- 

 lusca, was for a long time doubtful, until in 1845 Mr. Austin assigned them to 

 the Pteropoda, which position is accepted by all the naturalists up to the pres- 

 ent day, though doubts are sometimes expressed as to their relation with the 

 thin hyaline shells of most of the existing forms of Pteropoda. 



Tentaculites scalariformis. HALL. 



Plate XXXI., figure 12. 



Tentaculites scalaris, Hall. Geol. of N. Y., 4th Dist., p. 1721843. 

 Tent, scalariformia and T. stcula. Hall. Illust. of Dev. Fossils 1876. 

 Tentaculites scalariformis, Hall. Pal. N. Y., Vol. 6, pt. 2, p. 1671885. 



Shell elongate-conical, straight, somewhat more cylindrical in approaching 

 the aperture ; the apex in well preserved specimens extremely attenuate, and 

 quite solid for one-fourth to one-third of the entire length of the shell. Annu- 



