ECHINODERMATA - KU ScholarWorks - University of Kansas

88 THE UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS
cryptodeltoids, and a hypodeltoid on anal side; hydrospire
plate present; approximately twice as many
pores as side plates along the deltoid and radial margins,
one curved or straight hydrospire fold on each
side of an ambulacrum; deltoids overlap radials, lancet
exposed along middle one-third of its width; shape of
calyx elliptical. Lower Carboniferous, England.
Remarks.—The genus Orbitremites was probably
derived from Ellipticoblastus by overlap of radials by
the deltoids.
ORBITREMITES DERBIENSIS (Sowerby)
Plate 44, figures 8-12; text-figs. 179-182
Pentremites derhiensis SOWERBY, 1825, pl. 11, fig. 3.
Description.—Calyx calcitic, flattened ellipsoidal in
side view, circular in top view, 7.5 mm. long by 7.5 mm.
wide, with periphery at mid-height. Stem impression
round, 1 mm. in diameter, moderately deep concavity.
Basal circlet pentagonal in basal view, 1.5 mm. in diameter,
in basal concavity, with three normally disposed
basals. Radials five, short, wide, pentagonal in side view,
recurved below, each 4 mm. long by 3.5 mm. wide, with
short, flat, narrow sinus 3 mm. long by 0.75 mm. wide,
and 110 degree angle of radial limbs at radiodeltoid suture,
with center at interradial suture. Deltoids overlap
radials.
Deltoids four, long, broadly lancet-shaped, each 6 mm.
long by 3.5 mm. wide, pierced in the adorai tip by one
oval spiracle, with deltoid lip adjacent to oral opening.
On the anal side the anispiracle is between the V-shaped
small epideltoid and large elongate pentagonal hypodeltoid,
with the two small cryptodeltoids (hidden beneath
the hypodeltoid) on either side of the anal opening,
internally separating the anal opening from the adjacent
hydrospire canals. The cryptodeltoids are infolded
to form the hydrospires and hydrospire plate on the anal
side. The oral opening is surrounded by four deltoid lips
and the superdeltoid, and is surrounded by five spiracles,
or four spiracles and an anispiracle. One long curved
hydrospire fold occurs on each side of an ambulacrum,
ending admedially in a hydrospire plate.
Ambulacra five, linear, each 9 mm. long by 0.75 mm.
wide, recurved below, with lancet exposed along the
median one-third of its width almost to the aboral tip,
and approximately 30 side plates in a space of 10 mm.
along an ambulacrum. The side plates are normally disposed,
with a subtriangular outer side plate resting on the
abmedial-adoral bevelled corner of each primary side
plate, two pores to each side plate along the deltoid and
radial margins, and five cover-plate sockets to each side
plate along the main food groove. The surfaces of the
calyx plates are ornamented by minute granules arranged
along growth lines subparallel to plate margins.
Occurrence.—Lower Carboniferous, Cockleshell beds
of the Middle Limestone of Yarnbury, near Grassington,
Yorkshire, England.
Types.—Plesiotypes, 328, 4, 5, one unnumbered (four
specimens), Harold Beaver collection, sent by DR. JOYSEY,
from Cambridge; Humble Oil & Refining Co., Houston,
Texas. The description is mainly that of specimen 328.
ORBITREMITES CAMPANULATUS (M'Coy)
Plate 43, figures 4-6; text-figs. 183-185
Pentrenutes cam panulatus M'Coy, 1849, p. 249; 1854, p. 123, pl.
3-D, fig. 9.
Description.—Calyx calcitic, fragmentary, 7.5 mm.
wide, with flat base, and periphery just above base. Stem
round, crenellar, 1 mm. in diameter, with approximately
30 crenellae, and a small central round lumen. Basal
circlet pentagonal in aboral view, 2 mm. wide, in broad
basal concavity. Radials five, pentagonal in side view,
presumably reaching to one-half the height of the calyx,
each 5.5 mm. long by 4 mm. wide, recurved below, with
a long, narrow, shallow sinus 5 mm. long by 1.25 mm.
wide. Upper portion of calyx destroyed but presumably
like O. ellipticus, with four deltoids, and a superdeltoid,
two cryptodeltoids, and hypodeltoid, and five spiracles.
Hydrospire plate present along deltoid and radial margins,
with two pores to each side plate and one long
straight hydrospire fold on each side of an ambulacrum.
Deltoids overlap radials. An angle of 115 degrees is
formed by the radial limbs at the radiodeltoid suture,
FIGURE
EXPLANATION OF PLATE 27
PAGE
1-11. Eleutherocrinus cassedayi SHUNIARD & YANDELL, Middle
Devonian, Hungry Hollow Formation (coral zone of Widder
beds), near Thedford, Ontario.-1 5. Plesiotype,
E15,933, Charles Southworth coll., Buffalo Soc. Nat. Sci.;
old quarry on Frank Hunniford farm near Thedford, Ontario;
1, oral view ( X4.5); 2, "D" ambulacral view
( X4.1); 3, aboral view ( X4.3); 4, "B" ambulacral view
( X4.3); 5, "C" atnbulacral view ( X5)-6 8. Plesiotypes,
E13,061, Charles Southworth coll., Buffalo Soc.
Nat. Sci.; 6, aboral view of polished section of "E" ambulacrum
( X10); 7, view looking adorally of polished
section of "D" ambulacrum of another specimen ( X 11) ;
8, aboral view of an ambulacrum near aboral end of another
specimen, showing thick radial plate beneath lancet
( X15). 9 11. Plesiotype, 3,665, Geol. Survey Canada;
9, "D" ambulacral view ( X3.7); 10, 11 , oral and aboral
views (X4.1) 72