Notes on Cincinnatian Fossil Types 
321 
29. Crania socialis, Ulrich 
{Plate VI, Fig. V, Plate III, Figs. 11 A, B) 
1878. Crania socialis Ulrich, Jour. Cincinnati Soc. Nat. Hist., 1, p. 98, Plate 4 , 
Fig. IJf 
1892. Crania socialis Hall and Clarke, Pal. New York, 8, pt. 1 Plate 4 H, Fig. 29 
The types of Crania socialis, including in addition to the speci- 
mens figured by Ulrich and by Hall and Clarke in the publications 
cited above, also several additional specimens, belong to the col- 
lection of Prof. Charles Schuchert, of Yale University, and were 
found at different elevations in the Eden group at Cincinnati, 
Ohio. 
The type figured by Ulrich (fig. 4 on plate 6 of present bulletin),* 
is a free upper valve resting upon a rock fragment containing Crypto- 
lithus tessellatus {Trinucleus concentricus) , and probably was found 
in the lower half of the Eden group. It is 2 mm. in length, 4.5 
mm. in width, and has a convexity of about two-thirds of a milli- 
meter. It is crossed by 7 vertical ridges, evidently representing 
the same number of columnals on that part of the crinoid stem to 
to which it was attached. There are faint traces of minute con- 
centric striae but no evidences of granules or radiating striae. 
The specimen figured by Hall and Clarke consists of a circular 
crinoid stem about 12 mm. in length and 3.3 mm. in diameter, with 
14 columnals, alternating in size, in a length of 10 mm. Both the 
larger and smaller columnals are repeated in the broad ridges crossing 
the Cranias. Of the latter, there are 10 attached to the crinoid 
stem fragment. The longest diameter of the Cranias is parallel 
to the length of the crinoid stem. There is no clear evidence of 
minute radiating strise. 
In a third specimen, C, there are 10 Cranias attached to a 
crinoid stem fragment 17 mm. in length; of these 6 are quite con- 
spicuous, and on one of them radiating strise diverge very distinctly 
from an apex situated near one end of the longest diameter of the 
specimen. On one of the other shells these markings appear more 
like granules strongly elongated in a radial direction; in this shell 
the apex is situated along the shorter diameter. 
Traces of radiately elongated granules are seen also on Cranias 
attached to specimens D, and E. 
One of the most elongated shells occurs on Specimen F. In 
this shell the length is 7.5 mm., the transverse diameter is 2.2 mm. 
and the apex at present rises fully 2 mm. above the curvature of 
