﻿248 



Cincinnati Society of Natural History. 



2. L. circularis, Miller and Dyer. 



Trocholitcs circulates ; M. and D., 1878. Contri. to Pal. No. 2, p. 9, 

 PL 3, fig. 10. 



T minusculus, M. and D. Ibid, PI. 3, fig. 11. 



Shell planorbiform ; volutions three to five, gradually enlarging to 

 aperture, and deeply embracing; section sub-circular or sub-elliptical ; septa 

 straight or directed backward, arched ; apex profoundly and equally 

 depressed on each side, perhaps perforated; body chamber long, consti- 

 tuting more than half the last volution ; aperture deeply notched on outer side ; 

 surface markings unknown. 



Localities : Morrow, Ohio, and Cincinnati. 



The differences between these two species (Z. circularis and L. minus- 

 cufas,) are insufficient for two species, and no more than individual 

 variations or those produced by difference in locality. One was described 

 from Cincinnati and one from Morrow, Ohio. 



3. L. baeri, Meek and Worthen. 



Trochoceras (?) baeri, M. and W., 1865. Pro .Phil. Acad. Nat. Sci. 

 for 1865, p. 263. 



Trochoceras (?) baeri, Meek, 1873. P aL of Ohio, I, p. 157, PI. 13, 

 fig. 9. 



Trochoceras baeri. Miller, Cin. Qua. Jour. Sci., II, p. 134. 



Shell sub-discoidal, with two or three rather rapidly enlarging whorls, 

 more broadly rounded on the outer surface than the side, and one-fourth 

 wider than high; each inner whorl impressing inner side of succeeding ; 

 umbilicus a little more than one-half dorso-ventral diameter of outer 

 volution and showing all inner volutions ; spire apparently scarcely rising 

 above upper surface of last turn; septa concave on side facing aperture; 

 separated on outer side of whorls by spaces, all showing very slight back- 

 ward curve on periphery and passing nearly straight across each side ; 

 surface, siphuncle and non-septate, unknown. 



Locality : Richmond, Indiana ; upper part of the group. 



Meek and Worthen in the original description refer this species to 

 Twchoceras with a mark of doubt, and say that it may belong to Lituites. 

 Meek in Ohio Palaeontology — vol. I, p. 157 — again says: " The specimen 

 from which this description was drawn up was defective on one side, so 

 that it is not easy to determine whether or not its whorls are coiled in 

 exactly the same plane, though they have the appearance of being some- 

 what oblique, and hence it was placed provisionally in the genus Trocho- 

 ceras. Should it be found, however, when better specimens came to be 



