BULLETIN OF THE LABORATORIES 
.18 
thickened by callus, which is sometimes in the form of a broad, prom- 
inent lobe, and that at the median line ; the last volution is always 
marked by- one strong, rugose or nodose median carina, which extends 
from the inner Ifp to the front margin ; in most cases there is a more 
or less distinct revolving ridge at each side of the median carina, and 
of equal extent with it ; the whole surface is also marked by strong 
transverse wrinkles and lines of growth, but sometimes the lateral 
ridges are wanting. Length and breadth equal. 
This species is represented by several recognizable fragments from 
Flint Ridge and Bald Hill. The description is quoted for reference. 
Bellerophon noclocarinatus , Hall {fide White.) 
(Plate III, Fig. 3.) 
A number of specimens of a rather large Bellerophon are in ex- 
actly the condition figured by White, in the 13th report of the Geologi- 
cal Survey of Indiana. The lip seems to be but slightly expanded ; 
general form, sub-globose; dorsal surface of outer volution, with a 
subnodose median carina which is divided by a furrow, in which at the 
bottom is a slightly raised line ; on either side the carina a broad, shal- 
low sinus ; proximally the volution marked by prominent distant re- 
volving ridges and the carina disappears ; the carina seems to termi- 
nate in a slight dorsal emargination of the lip. 
None of our specimens preserve the aperture or umbilicus. 
White is inclined to believe his B. inspeciosus a variety of this species. 
Bellerophon {sub-cordiformis, sp. n.) 
(Plate II, Fig. 7 a, b, c. ) 
A fragment of a small Bellerophon may be noticed, which appears 
to, indicate a species entirely distinct from any known to the writer. 
Neither the mouth nor the umbilicus is visible,^ but the last coil is evi- 
dently very rapidly enlarged. The outline, as viewed from behind, is 
cordate; the diameter in the plane of the coils nearly equal to the 
width ; middle of outer coil carinate, lip apparently regularly expand- 
ed; surface marked by oblique, revolving, rounded ridges, springing 
from the median carina and passing toward the lip, between these 
ridges are impressed lines, containing prominences disposed at regular 
intervals. This peculiarity of the surface markings alone is thought 
characteristic. Width, over 0.4 in., height about the same. Should 
