INSERTAE SEDIS 
139 
INSERTAE SEDIS 
Parastephanocrinus typus new genus and species 
Plate 31, figs. 12-120 
Dicyclic. Calyx small, low and broad, height to width 5 to 7 mm., with a 
concave base. IBB 5, at the bottom of the cavity. BB large, elongate, forming 
more than half the bulk of the calyx, curving upwards, and elevated into high 
median ridges which branch to the next plates; post. B rises above the others 
to about half the height of RR, curving inward to the anal opening. RR much 
smaller exteriorly, but massive, extending deeply in toward the oral center, and 
forking into strong projecting processes at either side which meet and abut in 
pairs, except at the posterior interradius where they are separated by the anus ; 
they are deeply indented medially by grooves for ambulacra toward the central 
cavity, with narrow, round facets facing outward, and occupying about one 
third the width of the plate. Anal opening at the margin between RR and post. B. 
Plates of tegmen unknown, but the central space was probably filled by solid orals. 
The first thought on looking at the ventral side of this crinoid is of the ever-puzzling 
Stephanocrinus. The deep ambulacral grooves, and the paired processes of the forked radials, 
are substantially on the same plan ; the open space at the center is just right to accommodate 
a set of interlocking orals, with covered ambulacra passing under them. But the dicyclic base 
and concave cup must exclude it from that genus, and the only recourse is to propose a new 
genus for its reception ; in doing so, I recognize how limited our understanding of it is. From 
the form and position of the facets it is improbable that the arms could have been like those 
of Stephana crinus ; but at all events they were small. As an aid to the discussion, I give some 
figures showing the leading characters of Stephana criniis. 
Harizan and lacality. Louisville limestone, Niagaran ; miles east of Bob, Decatur 
County, Tennessee. 
Stephanocrinus angulatus Conrad 
Plate 31, figs. 13-16 
Stephanocrinus Conrad, Jour. Acad. Nat. Sci., Phil., 8, 1842, p. 278; p. 279, pi. 15, fig. 18. — Wachsmuth 
and Springer, Rev. Pal., 3, 1886, p. 291. — Bather, Treatise on Zool, 3, 1900, p. 97, fig. 2, p. 145. — 
Zittel-Eastman, Textb. Pal., 2d ed., 1913, p. 207. — Jaekel, Phylogenie und System, 1918, p. 109. — 
Wanner, Permischen Blastoiden von Timor, 1924, p. 186. — Bassler, Bibliogr. Index, 1915, p. 1187 (com- 
plete synonymy and list of species). 
This genus is of debatable systematic position, and has been variously con- 
sidered by different authors as a crinoid, a cystid or a blastoid. In favor of the 
first view are the branching, biserial arms ; while the forked radials, resemblance 
of the orals to the deltoids, and the orientation of the small basal in the r. ant. 
interradial position instead of the 1. ant., as in crinoids with 3 basals, are all 
characters which tend toward the blastoids. I am figuring some specimens of 
the type species from Lockport, New York, and aijother from Tennessee, for 
