A Neiv Cystocrinoidcan Species. — Sardeson. 269 
These fossils are not unlike fossil medusae in a gross way, but 
they have a pentameral symmetry. Rarely, the black film-like 
coating may be thicker and with increasing thickness the dark 
color lessens. The best specimens are low, conical, whitish 
lime bodies with crystalline cleavage, smooth surface and cen- 
tral stump of a broken ofif crinoid stem. When well preserved 
the surface, if dampened, shows suture lines (fiigs. 14, 15, pi. 
xii), and the disc is seen to be composed of radiating rows of 
plates with close sutures. Another specimen (pi. xii, fig. 16) 
has an etched or macerated surface on which ridges occupy 
the position of the radiating rows of plates and branching 
furrows between them mark the sutures. Transverse sutures 
also appear on the macerated surface, but much less distinctly 
than the radiating ones. In the first stages of maceration, 
apparently, the furrows along the transverse and the radiating 
sutures are equally deepened, but later the latter rapidly ex- 
ceed the former, probably because they merge into parallel 
internal canals. Five ridges or corresponding five primary 
rows of plates arise from the central stem or stump and radiate 
to the margin. Other ridges or rows of plates intercalate 
between them. The furrows or suture lines branch correspond- 
ingly. The arrangement of the plates and sutures around the 
stump or base of the stem is unfortunately obscured in all my 
specimens by discoloring or by injury, but very probably they 
simulate a crinoidean or cystidean calyx. Also it is not readily 
determinable in the specimens whether the disc comprises one 
or two or three layers of plates, except that one of the stumps 
indicates two layers. The margin of the disc may be partly 
lobate, or may be far from circular as in the specimen figured 
(pi. xii, fig. 14). In this case the rows of plates may be not 
very regular, as in one place where the rows intercalate in 
such a manner that there seems to be only one plate in each 
row. Normally, the structure is comparable to a crinoidean 
stem base with numerous branching laterally appressed cirri. 
Discussion. 
This new crinoid is especially interesting when compared 
to both Crinoidea and Cystoidea. As well known, the Cri- 
noidea are now thought to have been derived from the Cys- 
toidea, and in that relation the Cystocrinoidea or crinoidean 
