NATURAL SCIENCES OF PHILADELPHIA. 
261 
and descriptions of the species above cited, that we have thus far failed to find 
any reliable diflFerences by which they can be distinguished. If these are really- 
identical with F. cylindrica it not only proves that species to have had an im- 
mense geographical range, but to have existed through vast periods of time, 
since, according to Murchison de Verneuil andKeyserling, it is widely distribu- 
ted in Russia, where it only occurs in the upper part of the lower carboniferous 
or mountain limestone series; while in Kansas it ranges through a great thick- 
ness of upper carboniferous rocks, much of which appears to be even more 
modern than most of the western coal measures. 
F. cylindrica var. ventricosa. 
Along with the forms above mentioned, which we regard as probably identical 
with Fasulina cylindrica, we find in some of the upper members of the coal mea- 
sures in Kansas, others differing so much in size and form, that we even suspect 
they may possibly belong to a distinct species. These we propose to designate 
for the present as a variety of F. cylindrica^ under the name of ventricosa^ which 
will be a good specific name, should they prove to be distinct. They differ 
from F. cylindrica^ as figured in Murchison de Verneuil and Keyserling's work 
on the geology of Russia, in being much larger, some of them measuring nearly 
half an inch in length, and 0.20 inch in diameter at the middle ; they are also 
proportionably much more ventricose, and differ in being usually less symme- 
trical, in consequence of ane side being more gibbous than the other. The 
transverse grooves marking the position of the septa also pass across the central 
ventricose region with more of a lateral curve than in the Russian specimens ; 
while the edges of the septa themselves, when the outer shell is removed, are 
seen to be apparently less distinctly waved. Again the aperture in all our 
specimens is so very narrow as to appear entirely closed. 
In the description of the Russian specimens it is said that young individuals 
are proportionably so much shorter and more fusiform than the old, that they 
might readily be mistaken for a different species ; exactly the reverse, however, is 
the case with our Kansas specimens, the smaller individuals being more nearly 
cylindrical, while they appear to have become more gibbous with age, until in 
some cases they might be described as subglobose. 
Locality and position. — This variety is found at Juniata on Blue river, and at 
Manhattan on the Kansas, far above all the coal beds yet discovered in Kansas. 
Orthisina crassa, n. sp. 
Shell thick, of medium size, §ubquadrate, rather compressed ; hinge, gene- 
rally a little less than the greatest breadth of the shell, but sometimes equal- 
ling it. Front broadly rounded ; lateral margins more or less arcuate, in 
some examples nearly straight. Surface ornamented by numerous straight ra- 
diating striaj, numbering near the beaks about thirty to forty on each valve, but 
increasing by the implantation of others between them, from one hundred, to 
about one hundred and twenty four, around the margin ; these striae are crossed 
by numerous fine elevated concentric lines, which are not only quite distinct in 
the spaces between, but on well preserved specimens are prominent on the stri» 
to which they impart a sub-crenulate aspect, as seen by the aid of a lens. Adult 
specimens also generally have several strong concentric imbricating marks of 
growth. 
Larger or ventral valve nearly flat, cardinal edge sloping a little towards the 
lateral margins ; beak not very prominent or distinct, not incurved, sometimes 
a little twisted to one side ; area rather broad, flat, and inclined obliquely beyond 
the cardinal edge of the other valve ; deltedium thick and prominent. 
Smaller or ventral valve moderately convex in the middle, concave on each 
side of the umbo, which is generally depressed : mesial tooth strong, and prom- 
inent, bifid. Length of a specimen a little above the average size 1*25, inch, 
breadth, 1-30 inch : transverse diameter of the two valves 
Locality and position — Leavenworth City, K. T., in Coal Measures. 
1858.] 19 
