178 PALAEONTOLOGY OF KENTUCKY. 



Loxonema hydraulicum. HALL AND WHITFIELD. 



Plate XX., figures 8 and 9. 



Loxonema hydmulica, H. and W. 24th Regent's Rep., p. 1931872. 

 Loxonema hydrautica, H. and W. 27th Reg. Rep., pi. 131875. 

 Loxonema hydraulica, H. and W. Illust. of Dev. Fossils, pi. 13 1876. 

 Loxonema hydraulicum, Hall. Pal. N. Y., Vol. 5, part 2, p. 44 1879. 



Shell turreted ; volutions rounded, from live to eight and more ; greatest 

 convexity about the middle of each ; upper ones always missing, and, therefore, 

 unknown. Sutures deep, giving a constricted aspect at the junction of the 

 volutions. 



Surface marked with distinct, angular striae, bending gently backward from 

 the suture to the periphery, and with a longer forward curve to the base of 

 each volution; those of the last volution bending more abruptly backward, 

 and making a second abrupt retrorse curve to the columellar lip. 



This species, in the rotundity of the volutions, and the constriction at the 

 sutures, contrasts with all the other species of this genus here described. 



Formation and Locality. Found rather plentiful in the cherty layers overlying the hydraulic 

 limestone of the Devonian formation, at and around the Falls of the Ohio, in Kentucky and Indiana, 

 associated with Lox. laeviusculum and Lox. rectistriatum. 



Loxonema laeviusculum. HALL. 



Plate XXII., figures 8 and 9. 

 Loxonema laeviitsculum, Hall. Pal. N. Y., Vol. 5, part 2, p. 1311879. 



Shell elongate, subulate ; volutions from nine to twelve ; rounded and some 

 what rapidly expanding to the last one, which is moderately ventricose. Su- 

 ture close and simple. Aperture ovate; the columellar lip much extended 

 below. 



Surface nearly smooth, or marked by faint, obsolescent striae, which are 

 moderately curved over the convexity of the volution, and become fasciculate 

 on the lower side of the last one as they approach the columellar lip. 



This species has the general aspect of Loxonema hamiltoniae, but it is less 

 rapidly tapering towards the apex, the volution somewhat less convex, and the 

 last one not so ventricose as in well preserved specimens of that species. Usu- 

 ally the specimens have the appearance of being worn and macerated, and the 

 general absence of striae upon the surface may be due in part to this cause ; 

 but they are associated upon the same surface with L. hydraulicum, which, 

 in similar conditions, has retained its surf ace- striae in good preservation. This 

 species is readily distinguished from L. hydraulicum by the less rounded volu- 

 tions and slighter constriction at the suture. It is more rapidly tapering than 



