ECHINODERMATA - KU ScholarWorks - University of Kansas

90 THE UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS
PENTREMITES GODONI (Defrance)
Text-fig. 188
encrina Godonii DEFRANCE, 1819, p. 467.
Asterial fossil PARKINsort, 1808, p. 235, pl. 13, figs. 36-37.
Description.—The new holotype is 17 mm. long by
15 mm. wide, with vault 15 mm. long, pelvis 2 mm.
long, and pelvic angle 145 degrees. The shape of the
calyx is subrounded in side view, and rounded pentagonal
in top view. Stem round, 2 mm. wide. Basal circlet
pentagonal in aboral view, 8 mm. in diameter, with three
normally disposed basals. Radials each 10 mm. long by
7 mm. wide, overlapping deltoids, with petaloid sinus
areas. There are five hydrospire folds on each side of an
ambulacrum.
Deltoids five, each 8 mm. long by 4 mm. wide, with
one oval spiracle excavated in the adoral tips of each, including
the anispiracle excavated in the anal deltoid. Oral
opening surrounded by five deltoid lips and five lancet
stipes, and each spiracle bordered by a deltoid lip,
lancet stipe, side plates, and deltoid body if side plates
are removed. On the anal side the deltoid lip is attached
to the deltoid body by two anal septa that separate the
anal opening from the adjacent hydrospire canals internally.
The septa are infolded to form hydrospires.
Ambulacra five, broadly petaloid, with lancet exposed
its full width, and 32 side plates in a space of 10 mm.
along an ambulacrum. A single pore occurs between
side plates along the deltoid and radial margins, and the
outer side plates rest on the bevelled abmedial-adoral corners
of each side plate. The specimen is silicified but
on others the ornamentation consists of fine growth
lines subparallel to plate margins.
Remarks.—The original suite of specimens of PARKIN-
SON, MITCHILL, SAY, WOODWARD, DEFRANCE, and FEATHER-
STONEHAUGH have been destroyed and therefore neotypes
are herein erected.
Occurrence.—Upper Mississippian (Chesteran), Gasper
Formation ( ?upper part), Bowling Green, Kentucky.
The original type specimen probably came from Mammoth
Cave, Kentucky, but the above specimen agrees
well with the figure of the type, and it is possible that the
type actually came from the Bowling Green area.
Types.—Neotypes, 139,103 (new holotype), 139,104
(new paratype, a polished section), old no. 8,437, identified
by HAMBACH as typical of the type, U. S. National
Museum, Washington.
PENTREMITES BURLINGTONENSIS
Meek & Worthen
Plate 54, figures 4-5
Pentremites burlingtonensis MEEK & WORTHEN, 1870, p. 33; 1873,
p.461, pl. 8, fig.?.
Description.—The illustrated specimen is here selected
to show form of the calyx with attached brachioles. Of
importance also is the fact that one specimen in the collection
of the Philadelphia Academy of Science apparently
has two hydrospire folds on each side of an ambulacrum.
This is the minimum number of folds reported
in any species of Pentremites.
Types and occurrence.—Plesiotypes, S3,634, two specimens
of four labelled Metablastus lin eatus, Springer collection,
from Lower Mississippian, lower part of Burlington
Limestone, Burlington, Iowa, U. S. National
Museum, Washington.
PENTREMITES PYRIFORMIS Say
Plate 54, figures 1-3
Pentremites pyriformis SAY, 1825, P. 294; 1825, p. 314.
Description.—The specimens here illustrated show
the form of the calyx with attached brachioles.
Occurrence.— Upper Mississippian (Chesteran),
Huntsville, Alabama.
Types.—Plesiotypes, three unnumbered specimens on
a card, U. S. National Museum, Washington.
Genus PETALOBLASTUS Fay, n. gen.
Type-species, by original designation (herein).—Pentremites ovalis
GOLDFUSS, 1829.
Generic diagnosis.—Spiraculate blastoids with five
spiracles, or four spiracles and an anispiracle, with
anispiracle between an epideltoid and hypodeltoid,
radials overlapping deltoids but radiodeltoid suture
inverted V-shaped opposite that of Pentremites, lancet
exposed its full width, with petaloid ambulacra,
one pore between side plates along deltoid and radial
margins, at least four hydrospire folds on each side of
an ambulacrum, and shape oval in side view. Lower
Carboniferous (Etroeungtian) Germany.
Remarks.—The genus Petaloblastus was probably
derived from Cordyloblastus by fusion of the superdeltoid
and cryptodeltoids into an epideltoid, and
downward migration of the deltoid plates, together
with outward migration of the lancet plate.
PETALOBLASTUS OVALIS (Goldfuss)
Plate 35, figures 1-8; text-figs. 189-192
Pentremites ovalis GOLDFUSS, 1829, p. 161, pl. 50, figs. la-c.
Description.—Calyx calcitic, oval in side view, pentagonal
in top view, slightly crushed, 6.5 mm. long by 4
mm. wide, with vault 4 mm. long, pelvis 2.5 mm. long,
pelvic angle on supplementary basals 10 degrees and on
radial bodies 145 degrees, with periphery above midheight.
The stem is round, crenellar, 0.5 mm. in diameter,
with small round lumen. Basal circlet conical in side view,
pentagonal in aboral view, 2 mm. long by 2.5 mm. wide,
with three normally disposed basals and three low ex-