282 FIELD COLUMBIAN MusEuM — GEOLOGY, VoL. II. 
altogether before the center of the plate is reached. Sutures obscure, 
not marked by grooves. 
Basal plates three, about equal in size. Two are pentangular and 
one is quadrangular. Together they form an obconical cup comprising 
about half the height of the calyx, triangular at the base and circular 
at the top. There is a slight circular depression in the center of the 
base for the reception of the column. Radial plates five, equal in 
size with the lateral edges produced into interradial processes. Height, 
aside from the processes, about equal to that of the basals. The 
characters of the vault are quite obscure, but appear to correspond 
with the description of the genus. 
This species is based on a single silicified specimen(Mus. No. P 8416) 
in a fairly good state of preservation. Its obconical form renders it so 
unlike all other species of the genus that comparison with them seems 
to be superfluous. The following measurements, in millimeters, taken 
from the type specimen, may be of use for comparison in case other 
specimens are found. 
Diameter at bases. a's. 102. eee 2.3 mm 
Diameter at top of basals\... 2 3) ee es ey 
Diameter at‘top of calyx)... 0) a ae Oude 
Height of radials aside from spines,i) eee Ao Oren 
Height:of basals,. 7.14% 5. 3.002 Se EWao ri 
Heightvof calyx, -ras2. fac. Sa, eee 
Length of spines)". 0.20% 2.0 So ce Ei 60e8 
Locality: Collected by the writer in the fall of 1905 in the clay 
pockets of the Niagaran limestone at Romeo, Illinois. 
STEPHANOCRINUS SKIFFI, sp. nov. Plate LX XXIV, Figures 16-20. 
The calyx has a small triangular base. It expands rapidly to the 
top of the basals and moderately from that point on. The distal edges 
of the radial plates are excavated for the reception of the arms, thus 
forming five interradial processes. The plates of the dorsal cup are 
Grnamented with a series of acute prominent striae. These striae are 
oblique at and below the upper lateral angles of the radials, longitudinal 
on the middle of the radials and basals and transverse on the lower 
part of the basals. Sutures are obscure and do not interrupt the 
striae. 
Basal plates three, about equal in size, one quadrangular, two pent- 
angular. Together they form a funnel-shaped cup, triangular at the 
base and expanding very rapidly to the top. An acute angular ridge 
extends from the base to the center of each plate where it becomes 
lost in the longitudinal striae. The basal cup comprises about half the 
