ECHINODERMATA - KU ScholarWorks - University of Kansas

BLASTOID STUDIES 101
Occurrence.—Lower Mississippian, lower part of Encrinital
(Burlington) Limestone, Boone and Marion
Counties, Missouri.
Types.—Holotype, S3,735, with a green label in a
glass vial with two fragments with orange labels, Shumard
collection, of the Hambach collection, sold to
SPRINGER, now in U. S. National Museum, Washington.
HAMBACH evidently had some of SHUMARD ' S types in his
personal collection when he sold his collection to
SPRINGER. The type probably came from Marion County,
Missouri, judging from the label.
SCHIZOBLASTUS WINSLOWI (Miller & Gurley)
Plate 46, figures 3-5
Oranatocrinus wins/owl MILLER & GURLEY, 1894, p. 66, pl. 6, figs.
34-35.
Orbitremites winslowi BATHER, 1899, p. 32.
Description.—The calyx of the holotype is silicified,
imperfectly preserved, 11.5 mm. long by 12 mm. wide,
with vault 11.5 mm. long, pelvis flat, with periphery
above radiodeltoid suture. Stem round, 0.5 mm. wide.
Basal circlet pentagonal in aboral view, 2 mm. wide.
Radials five, each 8 mm. long by 6.5 mm. wide, pentagonal
in side view, extending to mid-height, with a 120
degree angle formed by radial limbs at radiodeltoid suture,
with center at interradial suture. The radial sinuses
are each 6 mm. long by 2 mm. wide. Deltoids overlap
radials.
Deltoids four, each 8 mm. long by 6 mm. wide, with
two spiracles notched in the adorai tip of each. It is presumed
that an anal opening was present between an epideltoid
and a hypodeltoid plate, and that two hydrospire
folds are present on each side of an arnbulacrum.
Ambulacra linear, long, recurved below, each 15 mm.
long by 2 mm. wide, with lancet exposed along main food
groove, but covered by side plates at the aboral end, and
30 side plates in a space of 10 mm. along an ambulacrum.
Side plates and pores normally disposed. The surfaces
of the deltoids and radials are covered by large aligned
nodes, with about eight nodes in three longitudinal rows
on each deltoid, and nine nodes in three aligned rows on
each radial, the rows being subparallel to the plate margins.
Occurrence.—Lower Mississippian, ?Burlington Limestone
(drift), at Danville, Illinois ( ?transported from
Burlington Limestone outcrops to the north).
Type.—Holotype, 6,621, one specimen, Walker Museum,
University of Chicago.
Genus TANAOBLASTUS Fay, n. gen.
Type-species, by original designation (herein).—Pentremites roerneri
SHUMARD, 1855.
Generic diagnosis.—Spiraculate blastoids with nine
openings around mouth, consisting of eight spiracles
and an anispiracle, with anispiracle between a superdeltoid,
and hypodeltoid, with two hidden cryptodeltoids,
deltoids moderately short, pores absent along
deltoid margins, with hydrospire plate and two pores
to each side plate along radial margins, two hydrospire
folds on each side of an ambulacrum, lancet exposed
along main food groove, interradial sutures even, base
flat to convex outward, radials overlapping deltoids;
form of calyx subelliptical. Mississippian, Missouri,
Montana, ?Arizona, Alberta.
Remarks.—The genus Tanaoblastus may have
been derived from some primitive type of Lophoblastus
in which the pores atrophied along the deltoids,
and the ambulacral margins of the radials infolded
to form two pores to each side plate, with reduction
of the number of hydrospire folds to two.
TANAOBLASTUS ROEMERI (Shumard)
Plate 36, figures 7-12; text-figs. 209-213
Pentremites roemeri SHUMARD (partim), 1855, p. 186, pl. B, fig. 2a;
1-1Amancx, 1884, pl. D, figs. 3, 3a.
Schizoblastus? roemeri KEYES, 1894, p. 137.
Cryptoblastus roemeri PECK, 1938, p. 60, pl. 26, figs. 19-21, 23-24.
Pentremites sampsoni HAMBACH, 1884, p. 551, pl. D, figs. 2, 2a.
Schizoblastus SaMpsoni ETHERIDGE & CARPENTER, 1886, p. 223.
Description.—Calyx calcitic, 6.5 mm. long by 5.5 mm.
wide, vault 6 mm. long, pelvis 0.5 mm. long, and pelvic
angle 150 degrees. The calyx is elliptical in side view,
with truncated summit, convex base, and periphery at
radiodeltoid suture about one-third of the distance down
from the summit. Stem round, 0.25 mm. wide, crenellar.
EXPLANATION OF PLATE 34
FIGURE PAGE
1-9. Placoblastus angularis (Lyox), plesiotypes, E11,629 (figs.
1-3,7), E9,057 (fig. 8), E9,058 (figs. 4-6,9), Reimann
coll., Buffalo Soc. Nat. Sci.; Middle Devonian, Ludlowville
Formation (Tichenor Limestone), Cazenovia Creek,
Springbrook, N.Y.; 1-3, oral, "D" ambulacral, and aboral
views of gerontic paratype of Nucleocrinus powelli REI-
MANN ( X 1.2); 4-6, oral, "D" ambulacral, and aboral
views of holotype of N. powelli ( X3); 7, detail view of
"B" ambulacrum of specimen shown in fig. I ( X13);
8, aboral view of another paratype of N. powelli ( X8);
9, oral view of specimen shown in fig. 4, showing what
appears to be several large plates between adorai tips of
cryptodeltoids, anal opening in black ( x2.6) 95