116 
Aug. F. Foerste 
7 occupy a width of 5 mm., separated by 3 or 4, sometimes 5, 
much less conspicuous striae. The striae of the pedicel valve 
are equal in number to those of the brachial valve, but the more 
prominent striae are relatively less conspicuous. 
One of the specimens belonging to the Schuchert collection has 
the following dimensions. Width along the hinge-line, 29.5 
mm.; across the center of the shell, 24 mm. Length of the pedi- 
cel valve, 21.7 mm.; of the brachial valve, 21 mm. Greatest 
convexity of the shell equals 8 mm. at 13.5 mm. from the beak; 
at this point the thickness of the shell is 5 mm. Length of the 
hinge-area, 29.5 mm.; height, 4 mm. In a more semicircular 
and more convex specimen from the same locality, belonging to 
set No. 3550 in the Chicago University collection, the greatest 
height of the shell is 10 mm. at 11.5 mm. from the beak; the 
length of the shell is 23 mm. 
Leptaena gibbosa, James 
{Plate I, Figs. 5 A, B, C) 
The types of Leptaena gibbosa, numbered 1114, are preserved 
in the James collection, in Walker Musum, at Chicago Univer- 
sity. Three of the types are illustrated very inadequately in 
the present Bulletin. The radiating striae are so fine that they 
are not indicated with the grating used in the preparation of the 
accompanying plate. Usually one of the median radiating stria- 
tions is stronger, sometimes two, and in one specimen, four of 
these median striations are stronger than any of the remainder. 
The other striae are very narrow and inconspicuous, about 20 to 
26 occurring in a width of 5 mm. The types were found 80 feet 
above low-water mark in the Ohio Liver, at Cincinnati, Ohio, in 
the Economy member of the Eden. Similar specimens were 
found 11 feet above the base of the Eden at Boyd, on the Ken- 
tucky Central division of the Louisville and Nashville Bailroad, 
and north of Ford, Kentucky, about a quarter of a mile before 
reaching the second railroad tunnel. In Leptaena invenusta, 
from the Gratz shale, 2 miles west of Drennan Springs, Ken- 
tucky, the number of radiating striae is about 15 in a width of 
5 mm. {Bull. Denison Univ., vol. XIV, plate VII, Fig. 3.) 
Cincinnati Quarterly Journal of Science, vol. i, p. 333, 1874. 
