ECHINODERMATA - KU ScholarWorks - University of Kansas

BLASTOID STUDIES 61
CRYPTOBLASTUS MELO (Owen & Shumard)
Plate 38, figures 6-9; text-figs. 98-100
Pentremites melo OWEN & SHUMARD, 1850, p. 65, pl. 7, figs. 14a-c.
Description.—Calyx calcitic, subspherical, 13 mm. long
by 11 mm. wide, with truncated summit and depressed
base. Stem round, 1 mm. in diameter, with approximately
40 crenellae extending almost one-half the radial distance
in from the circumference. Basal circlet pentagonal, 3
mm. wide, depressed in basal concavity, with three normally
disposed basals. Radials five, elongate, recurved
below, each 12 mm. long by 5.5 mm. wide, with narrow
sinus and depressed interradial sutures; radials overlapping
deltoids except at the adoral tip of radial limbs
where in reverse manner aboral ends of the deltoid bodies
slightly overlap the radial limbs, giving the appearance
that the radial limbs are wedged in the deltoid bodies.
Deltoids four, arrow-shaped, each 1.5 mm. long by 1.5
mm. wide, with two spiracles notched in the adoral tip
of each on the ambulacral margins, and without pores
along margins of the ambulacra. On the anal side a large
oval anispiracle occurs between an epideltoid and hypodeltoid,
but internally, in a specimen seen in the Philadelphia
Academy of Sciences collection, there probably
are two hidden cryptodeltoids beneath the hypodeltoid.
If this is true, the plate adjacent to the oral opening on
the adorai side of the anal opening should probably be
called the superdeltoid, instead of epideltoid.
Ambulacra five, linear, each 15 mm. long by 1.25 mm.
wide, recurved below, lancet exposed along the middle
one-third of its width except at the aboral end. The side
plates are normally disposed with 30 side plates in a
space of 10 mm. length along an ambulacrum. Four coverplate
sockets to each side plate are seen along the main
food groove and three side cover-plate sockets to each
side plate along side food grooves. Two hydrospire folds
occur on each side of an ambulacrum, with a hydrospire
plate on each side, and more pores than side plates (approximately
two to each side plate) along the radial margins.
The surfaces of the calyx plates are ornamented
with fine granules aligned parallel to plate margins.
The above description is based on the newly selected
holotype.
Remarks.—The original holotype was destroyed in a
fire at Indiana University in 1883, where the Owen
collection was housed. The neotype, or new holotype,
here selected, is that figured by ETHERIDGE & CARPENTER,
1886, pl. 7, fig. 14.
Occurrence.—Lower Mississippian, lower part of Burlington
Limestone, Burlington, Iowa (neotype).
Type.—Neotype (new holotype), S4,959, one specimen,
old number S3,766, Springer collection, U. S. National
Museum, Washington. This is also the type-species
of Cry ptoblastus.
CRYPTOBLASTUS SHUMARDI (Meek &Worthen)
Plate 38, figure 4
Granatocrinus shumardi MEEK & WORTHEN, 1866, p. 257.
Description.—The specimen is 36 mm. long by 17
mm. wide and is here illustrated to show the shape of the
specimen with brachioles attached.
Occurrence.—Lower Mississippian, lower part of Burlington
Limestone, Burlington, Iowa.
Types.—Topotypes, S3,765, 10 specimens, Springer
collection, U. S. National Museum, Washington.
Genus DEVONOBLASTUS Reimann, 1935
Type-species, by subsequent designation (Reimann, 1942) —l'entremites
leda HALL, 1862.
Generic diagnosis.—Spiraculate blastoids with five
spiracles, or four spiracles in addition to an anispiracle,
with anispiracle between a superdeltoid and hyperdeltoid
and with two hidden cryptodeltoids, approximately
five hydrospire folds on each side of an ambulacrum,
lancet covered by side plates except at adoral end, with
one pore between side plates along radial and part of
deltoid margins; deltoids visible in side view, overlapped
by radials; calyx form elliptical, with conical
pelvis. Devonian, New York, Ontario, ?Indiana.
Remarks.—The genus Devon oblastus was probably
derived from Hyperoblastus by complete closure of
the radial sinus, downward migration of the deltoid
plates, and partial outward migration of the adorai
end of the lancet plates.
EXPLANATION OF PLATE 16
FIGURE PAGE
1-3. Orophocrinus gracilis (MEEK & WORTHEN), topotypes,
S3,228, Springer coll., U.S. Natl. Mus.; Lower Mississippian,
Lower Burlington Limestone, Burlington, Iowa; 1,
oral view of specimen ( X4.4); 2,3, aboral and "D" ambulacral
views of another specimen ( X3.6) 37
4-6. Orophocrinus orbignyanus (DE KoNnvcx), topotype,
S3,229, Springer coll., U.S. Natl. Mus.; Lower Carboniferous
limestone, Tournai, Belgium; 4, oral view, ( X3.5);
5, "B" ambulacral view, ( X2.8); 6, aboral view, ( X3.7) 37
7-9. Orophocrinus verus (CUMBERLAND), plesiotype, S3,237,
Springer coll., U.S. Natl. Mus.; Lower Carboniferous limestone,
Lancashire, England; oral, "D" ambulacral, aboral
views (all X3.5) 39
10-12. Orophocrinus puzos (MONSTER), topotype, S3,230,
Springer coll., U.S. Natl. Mus.; Lower Carboniferous limestone,
Tournai, Belgium; oral, "D" ambulacral, aboral
views (all x6.6) 38