284 FIELD CoLUMBIAN MusEuM — GEoLocGy, VoL. JI. 
it rests, are in the form of a rhomb, with its transverse axis equal 
to the width of the radial plate. In S. skiff: the rhomb consists of nine 
striae, but in S. hammellt there are more than three times that 
number. In S. hammellt moreover the curvature of the rhomb con- 
forms to the general curvature of the calyx, but in S. skiff1 it is decid- 
edly convex transversely and moderately so longitudinally (PI. 
DXXXIVS Biswe0) 
The type specimen (Mus. No. P 8479) consists ofa natural cast and 
more than half the accompanying mold, both in an excellent state of 
preservation. Several other individuals of this species are in the 
collections. 
The specific name is proposed in honor of Mr. Frederick J. V. 
Skiff, Director of the Museum. 
Locality: Niagaran limestone of the spoil heaps of the Chicago 
Drainage Canal near Lemont, Illinois. 
Family ZOPHOCRINIDA. 
ZOPHOCRINUS 5S. A. Miller. 
Two new species belonging to this genus were collected by the writer 
and are here described. This genus differs from all other crinoids in 
that the calyx contains but four radial plates; the quadrangular one 
is somewhat larger than the others and is probably made up of the 
right and left posterior radials fused, as the tetramerism affects the 
dorsal cup only; the dome and arms are pentameral. 
aoa! 
Cpa 

‘Fig. 5. Outline of the (1) Posterior and (2) Ventral Views of the Genotype and (3) Diagram of 
Zophocrinus. (After Bather.) 
The plates are as follows: Basals three, two equal, one larger; 
radials four, three equal, one larger. The ventral disc is composed 
of five orals, the posterior oral is the largest and the two anterior orals 
