68 
Aug. F. Foerste 
I 
two systems of striations usually is seen best along the umbonal V 
ridge. No left valves have been found attached to the right valves, " 
but the left valves are believed to be less convex, with strong and 
distant lamellose lines of growth, similar to those on the right ; 
valves, but with radiating striations difficult to recognize even ' 
under an ordinary lens. Named in honor of E. O. Ulrich. 
Waldron bed: Newsom, Tennessee. 
In Rhomhopteria mira, the type of the genus Rhornhopteria, the , 
straight hinge line is continued both anterior and posterior to the 
beak; the left valve is more convex and displays the cross-striations. i 
With this species Rhomhopteria clathrata, described by Weller from ’-i 
the Coeymans limestone of New Jersey, is congeneric. Rhom- '|‘ 
bopteria ulrichi and Rhomhopteria revoluta differ in the absence 
of the anterior projection of the straight hinge line, and in the 
reversal of the valves, the right valve being the more convex one 
and possessing the conspicuous cross-striations. If these species fji 
possess teeth, cardinal or lateral, no trace of them has been found 
in the specimens at hand. Posterior to the beak, the hinge area J 
of the right valve is thickened for about half the length of the hinge :] 
dine, and against this thickened area the hinge margin of the left -! 
valve rests. The term JSfewsomella is here introduced to distin- ''i 
guish these shells from those typified by Rhomhopteria m.ira. 1 
Rhomhopteria (Newsomella) revoluta, Winchell and Marcy. 
{Flate IV, Figs. 63 A, B, C.) ' U 
Specimens either identical with Rhomhopteria revoluta, described \ 
by Winchell and Marcy from the Niagaran rocks of Bridgeport, 
Illinois, or closely related to this species, occur in the Waldron bed, 
at Newsom, Tennessee. The radiating striae are much coarser; 
12 to 14 striae occupy a width of 5 mm. at a distance of 10 mm. 
from the beak. The striations on the posterior wing diverge 
strongly from those on the anterior part of the body, and along 
the umbonal ridge, on the posterior side of the body, the two sys- f 
terns of striae cross. Cross striations are present also on the ante- 
rior lobe, only the right valve possessing these radiating striations. 
The striations on the posterior wing meet the hinge margin 
at angles of about 30° to 45°. The left valves are less convex, •! 
often nearly flat, and are marked by prominent, and rather distant 4 
lamellose concentric lines of growth. Between the latter, only i 
