ECHINODERMATA - KU ScholarWorks - University of Kansas

BLASTOID STUDIES 45
30 side plates in 10 mm. The lancet is approximately 1
mm. distant from the oral opening and confined to the
summit. The primary side plates are elongate, with long
side food grooves, and small normally disposed outer side
plates on the abmedial margins of the primary side plates.
There are five or six main cover-plate sockets along the
interdeltoid sutures and two or three sockets on the adoral
margin of each deltoid lip adjacent to the oral opening.
The surfaces of the calyx plates are worn but appear to
have fine growth striae parallel to plate margins.
Occurrence.—Permian beds, Krassnoufimsk, Urals,
USSR.
Types.—Metatypes, 695, one specimen, N. N. Yakovley
collection, upon which description is based, Illinois
Geological Survey, Urbana; 102,187, one specimen, N. N.
Yakovlev collection, old no. 16, one specimen, U. S. National
Museum, Washington.
Genus TFIAUMATOBLASTUS Wanner, 1924
Type-species, by original designation.—Thaumatoblastus longiramus
WANNER, 1924.
Generic diagnosis.—Fissiculate blastoids with ten
hydrospire fields, small anal opening between a large
epideltoid and a large hypodeltoid, a reduced number
of slits on the anal side, but seven or eight slits on the
other interambulacral areas, widely exposed, with long
lancet plates extended into winglike extensions of the
radials, lancet almost completely covered by side plates,
with rounded base and flat summit. Permian, Timor
Island, Indonesia.
Remarks.—The genus Thaumatoblastus was probably
derived from a form similar to Conoschisma, in
which the sinuses migrated outward and upward and
the radial limbs became winglike.
THAUIVIATOBLASTUS LONGIRAMUS Wanner
Plate 18, figure 12; text-fig. 56
Thaumatoblastus longiramus WANNER, 1924, p. 201, pl. 2, figs. 1 -
17; pl. 4, fig. 2; pl. 5.
Description.—The one specimen examined is a fragmentary
radial plate with lancet and side plates preserved.
The important observation that should be added to the
description given by WANNER iS that an outer side plate
is present on each primary side plate, normally disposed
on the bevelled abmedial-adoral corner of the primary
side plate. Also the lancet plate is almost completely covered
by the side plates.
Occurrence.—Upper Permian, Basleo beds, Basleo,
Timor Island, Indonesia.
Type.—Topotype, S4,053, three radial fragments,
Springer collection, U. S. National Museum.
Genus TRIONOBLASTUS Fay, n. gen.
[-=?Heteroschisma WACHSMUTH, 1883]
Type -species, by original designation (herein).—Pentremites subtruncatus
HALL, 1858.
Generic diagnosis.—Fissiculate blastoids with eight
exposed hydrospire fields, a superdeltoid, subdeltoid,
and presumably hypodeltoid on the anal side, hydrospire
slits absent on anal side, with lancet covered by
side plates, and form steeply conical in side view.
Middle Devonian, North America (Michigan, Ohio,
Indiana, Kentucky, New York, Iowa, Ontario).
Remarks.—The genus Trionoblastus was probably
derived from Decaschisma by fusion of the cryptodeltoids
into a subdeltoid plate and atrophy of the
hydrospire slits on the anal side.
TRIONOBLASTUS SUBTRUNCATUS (Hall)
Plate 4, figures 1-3; text-figs. 57, 58
Pentremites subtruncatus HALL, 1858, p. 485, pl. 1, fig. 4.
Description.—Calyx calcitic, obconical in side view,
pentagonal in top view, 11.5 mm. long by 7 mm. wide,
vault 2 mm. long, pelvis 9.5 mm. long, pelvic angle 40
degrees, periphery at radial lips well above mid-height,
with flat summit and conical base (broken). Basal circlet
elongate conical in side view, pentagonal in basal view,
5 mm. long by 5 mm. wide, with three normally disposed
EXPLANATION OF PLATE 10
FIGURE PAGE
1-3,8. Hyperoblastus goldringae (REImANN), 1-3, syntype
E9,049, Buffalo Soc. Nat. Sci.; Devonian, Ludlowville
Formation (Pleurodictyum beds), Cazenovia Creek, Gehle
farm, 0.12 mile below Transit Road bridge, N.Y.; 1-3,
oral, "D" ambulacral, aboral views (all X 7.5)-8,
plesiotype, E21,160, F. W. Wattles coll., Buffalo Soc.
Nat. Sci.; Devonian, Wanakah Shale (Pleurodictyum
beds), old quarry at Bay View, N.Y.; cross sec, of specimen
showing four hydrospire folds on each side of an
ambulacrum, aboral view ( X4) 33
4-6. Hyperoblastus juvenis (REimANN), syntypc, E9,054, Buffalo
Soc. Nat. Sci.; Devonian, Ludlowville Formation
(Pleurodictyum beds), old quarry at Bay View, N.Y.;
oral, "D" ambulacral, aboral views (all X11.1) 33
7. Hyperob1astus perovalus (REImANN), holotype, E12,267,
Buffalo Soc. Nat. Sci.; Devonian, Tully Limestone (pyrite),
Cazenovia Creek, Springbrook, N.Y.; side view ( X8) 33
9-11. Hyperoblastus leans (REimArnnt), syntype, E9,052, Buffalo
Soc. Nat. Sci.; Devonian, Ludlowville Formation
(Pleurodictyum beds), Athol Springs, N.Y.; oral, "D"
ambulacral, aboral views (all X4.6) 33