1889 .] 
297 
[Foerste. 
third or fourth of which is more prominent and distinct, but not 
more strongly elevated than in most forms of Leptcena sericea. For 
this form I suggest the name Leptcena transversalis , var. Alaba- 
mensis. 
6. Leptcena transversalis , var. intermedia, Ringueberg, published 
as a variety under L. sericea , is found in a hard limestone of blu- 
ish-green tinge, between the Clinton and Niagara strata proper at 
Gasport and Lockport, N. Y. The cardinal angles are rather prom- 
inently prolonged from the otherwise quite regular but strongly 
convex body of the shell. The beak is of medium width. The 
t} T pe specimen does not show striae, but others from the same lo- 
cality show tine radiating striae with a few more prominent striae 
intercalated. This form is quite small, the specimens seen from 
Ringueberg’s collection have a length of 4.7 mm. and a width of 
9.8 mm. 
7. Leptcena prolong ata, Foerste, from the Clinton group of Ohio, 
is represented perhaps in the Indiana collections by a fragmentary 
specimen with a width of 24 mm. and a length of, I think, at least 
10 mm. The anterior part of the shell is gone. It shows the 
elongated lateral angles and a trace of a median elevation. 
7. In collections made at Wildwood Station in Georgia, this 
form is very common, far more so than in Ohio, where it was first 
noted. It is characterized by the great lateral extension of the 
shell, the width equalling from 2.25 to 2.5 times the length of the 
shell. The ventral valve is much less convex than in Leptc&na trans- 
versalis , less convex at times indeed than in the variety elegantula. 
But still the valve is quite convex, especially towards the cardinal 
margin, where the shell is quite strongly curved. The anterior and 
lateral margins form a continuous regular curve, meeting the car- 
dinal margin at angles of about fifty degrees. In many specimens 
there is a faintly developed, broad median lobe. This lobe becomes 
fairly distinct, although always low in some specimens, in others it 
is entirely absent. The surface is marked by fine radiating striae, 
interspersed with which at quite regular intervals are single, broader 
and more elevated striae, which have about the same frequency of 
occurrence as in specimens of Leptcena transversalis of the New 
York Niagara. A feature noted in the Georgia specimens, but ap- 
parently not very constant, is the existence of corrugations along 
the cardinal margin, parallel to each other on each side of the valve, 
and having about the same direction as the lateral margins where 
