Gn L007. NEw CrINoIps — SLocom. 281 
tion. There seems to be no reason to doubt that they are specifically 
identical with the specimens from Tennessee on which the original 
description was based. 
Family STEPHANOCRINIDA&. 
STEPHANOCRINUS Conrad. 
Only one species of this genus has heretofore been recognized in the 
Chicago Area. Two new species have been collected by the writer and 
are here described. The generic characters are as follows: Basals three, 
about equal in size, two pen- 
tangular, one quadrangular. 
Radials five, equal, resem- | 
bling the forked plates of 
some Blastoids. These prongs 
form interradial processes, 
and between them are situ- 
ated the ambulacral grooves 
leading to the arms, which 
rise from a single axillary 
costal plate situated at the ! 
end of the sinus. Oral plates five, interradial in position and forming 
most of the ventral disc. They are not visible in a side view of the 
calyx. They join the inner surface of the radial plates and extend to 
the top of the interradial processes. Their lateral edges are in contact 
below the ambulacral grooves, but a space is left for the mouth at the 
center of the ventral disc. The anus is situated between the posterior 
oral plate and the adjoining process. 
This genus has been referred to the Cystoids and Blastoids by some 
writers, and while it undoubtedly has some characters similar to both 
it has been shown to be a Crinoid by Wachsmuth and Springer on 
account of its brachial plates. 
Fig. 4. Diagram of Stephanocrinus. 
STEPHANOCRINUS OBCONICUS sp. nov. Plate LX XXIV, Figs. 12, 13. 
The dorsal cup is obconical, truncated at the base, sides slightly con- 
vex, forming an angle of about 30 degrees. The surface of the plates 
is apparently smooth or finely granulose, following the curve of the 
calyx except near the proximal end of the basal plates, where they de- 
velop a median ridge giving a triangular form to the base. This ridge 
is most prominent at the base and rapidly diminishes, disappearing 
