1 
224 ^ ^ ' Foerste \ 
Hebertella alveata, nom. nov. ! 
{Plate IV, Figs. 8 A, B.) ; 
The types are greatly prolonged at the hinge line, and have a 
distinct and broad median depression along the brachial valve, | 
extending from the beak to the anterior margin of the shell. An- ! 
other form, apparently merging into the former, but narrower, Ij 
with the hinge line often slightly less than the width of the shell | 
across the middle, and with the brachial valve often more convex | 
from front to rear, occurs frequently in the Whitewater beds of | 
Richmond, Indiana. The latter form may be called Hebertella j 
alveata-richmondensis, and is mentioned only because at some |i 
localities it is common while the form with extended hinge line f 
may be absent. j 
Shells having the form of Hebertella alveolata begin their exist- j 
ence in the Liberty bed, and are widely distributed in the White- r 
water beds, in Ohio and Indiana. They were erroneously iden- I 
tified by Meek as Orthis occidentalis. \ 
In Hebertella occidentalis, Hall, from the Maysville formation, i 
as represented by the types preserved in the American Museum I 
of Natural History in New York City, where they are labelled 
as coming from Cincinnati, Ohio, there is only a faint median 
depression near the beak of the brachial valve, disappearing ante- 
riorly. This depression is scarcely discernible unless the shell is 
held in a favorable light. Judging from the types of Orthis sinu- |! 
ata, preserved in the same museum, the latter is only a more f 
coarsely plicate form Orthis occidentalis. j 
Austinella scovillei, Miller. l! 
Journal, Cincinnati Society of Natural History, vol, 5, p. 40, | 
1882. i 
Dinorthis scovillei belongs to a group of species typified by ji 
Orthis kankakensis, McChesney and including also Orthis luhit- |i 
-fieldi, N. H. Winchell. Orthis kankakensis and Orthis whit-jie^di l! 
were listed by Hall, Clarke, and Schuchert under Plectorthis. i 
Orthis scovillei was listed by them under Hebertella, but was 
placed by Nickles under Dinorthis. i 
The distinctly quadrate muscular scar of the ventral valve in 
these species suggests affinities with Dinorthis. This view is f 
