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shallow, containing an elliptical field of 12-15 small,
granulated pillars.
DISCUSSION.—Trochocyathus decamera is superficially
similar to T. japonicus but can be distinguished by having
decameral symmetry, a thin epitheca, and tertiary septa wider
than its secondary septa. In T. japonicus, the S4 (equivalent to
tertiaries of T. decamera) are less wide than the S3 (equivalent
to secondaries of T. japonica).
The genus Tethocyathus differs from Trochocyathus in
having a thick epitheca, Trochocyathus having only a thin or no
epitheca (Cairns, 1979:76-77). Therefore, T. decamera is
placed in Trochocyathus.
ETYMOLOGY.—The species name decamera (Greek: deka,
meaning 10, and meros, meaning division or parts) refers to the
decamerally arranged septa in 10 septal sectors.
MATERIAL EXAMINED/TYPES.—Holotype: TM (KT9202,
YT1), USNM 92693.-Paratypes: TM (KT9202, YT1), 1,
USNM 92694; TM (KT9015, CB1-2), 1, ORI. Type Locality:
30°15'N, 130°46'E (Osumi Shoto, northern Ryukyu
Islands), 80-88 m.
DISTRIBUTION.—Osumi Shoto, northern Ryukyu Islands and
off Mishima, Eastern Channel, Korea Strait; 70-88 m.
Trochocyathus cooperi (Gardiner, 1905), comb. nov.
PLATE 23f,g
Tropidocyathus cooperi Gardiner, 1905:955, pi. 93: fig. 30.
Trochocyathus.—Vaughan and Wells, 1943:48, fig. 20b.
DESCRIPTION.—Corallum (anthocyathus) a highly compressed
(GCD:LCD = 1.4-2.3), straight cylinder, with parallel
thecal edges and only slightly divergent thecal faces. Largest
Japanese specimen 13.4 x 8.6 mm in calicular diameter and
18.5 mm in height. Base of each thecal edge bears a downward
projecting crest up to 4.5 mm in length and flattened in plane of
GCD. Between these 2 crests is the basal scar of attachment,
which is elliptical to almost circular: 3.9-4.3 x 3.3-3.4 mm in
diameter. Only one small specimen is fully intact, still having
its anthocyathus attached to the fixed anthocaulus. It measures
7.3 x 3.9 mm in calicular diameter and 8.0 mm in height, with
2 edge crests, but it is assumed that the eventual transverse
division would have taken place about 3.3 mm from the basal
disc, just under the edge crests, where the cross sectional
diameter is about 4x3 mm. The holotype also has a partial
anthocaulus remaining attached to its base. Costae equal in
width (0.5 mm), flat, and granular (about 2 granules across a
costa), becoming slightly convex and separated by deeper
furrows near calicular edge. Corallum reddish brown, with
slightly more intense color and dark costal speckling in a
narrow band about 1.5 mm from the calicular edge.
Septa hexamerally arranged in 4 complete cycles:
S1_2>S3>S4 (48 septa); however, larger coralla often have pairs
of S5 in the end half-systems comprising up to 56-62 septa.
S,_2 little exsert (about 0.7 mm), extend about two-thirds
distance to columella, and have slightly sinuous inner edges. A
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY
slender (about 0.6 mm wide) palus sometimes occurs on the
inner edge of each S^, forming a deep-seated palar crown
directly adjacent to the columella, but often these pali are
missing or indistinguishable from columellar elements. S3 only
slightly less exsert (0.6 mm), about two-thirds width of S,_2,
and have sinuous inner edges. Each S3 bordered by a wide (up
to 1.1 mm) palus, together forming a prominent palar ring
encircling columella. S4 0.5 mm exsert and about threequarters
width of an S3. When present, pairs of S5 are quite
small. Fossa of moderate depth, containing an elongate
columella consisting of several papillae, some of which may be
indistinguishable in size and position with P1-2.
DISCUSSION.—Several caryophylliid genera reproduce
asexually by transverse division (Cairns, 1989b), Trochocyathus
being one of them. The original reference to transverse
division in this genus was Vaughan and Wells (1943:47), who
cited the process in two undescribed species from the
Philippines and in Trochocyathus hastatus Boume, 1903.
Bourne's species subsequently has been divided (Wells, 1984)
into two species: Stephanocyathus (A.) hastatus and
Bourneotrochus veroni Wells, 1984 (= Deltocyathus stellulatus
Cairns, 1984), the latter established for a spinose, discoidal,
deltocyathid-like species having transverse division. Therefore,
T. cooperi is the only described species of Trochocyathus that
is known to have transverse division.
The two syntypes reported by Gardiner (1905) are larger than
the Japanese specimens, having up to 10 pairs of S5 (68 septa)
and a better developed columella. The Japanese specimens
appear to be the first report of this species subsequent to its
description.
MATERIAL EXAMINED.—New Records: TM (KT9202,
YT1), 23, USNM 92691, 3, ORI.
TYPES.—Two syntypes of T. cooperi are presumed to be
deposited at the BM. Type Locality: Kolumadulu and
Suvadiva, Maldive Islands, 64-70 m.
DISTRIBUTION.—Off Japan: Osumi Shoto, northern Ryukyu
Islands; 80-88 m. Elsewhere: Maldive Islands; Philippines;
64-70 m.
Deltocyathus Milne Edwards and Haime, 1848a
DIAGNOSIS.—Solitary, discoidal to patellate, free in adult
stage. Well-developed costae present. Pali present before all
but last cycle; within each system the inner edges of each pair
of P3 fuse to the P2 near the columella, forming characteristic
chevrons (deltas). Paliform lobes may also be present before
fourth septal cycle. Columella papillose.
TYPE SPECIES.—Turbinolia italica Michelotti, 1838, by
monotypy.
Deltocyathus vaughani Yabe and Eguchi, 1932
PLATES 23/,./, 24a-c,f
Not Deltocyathus orientalis Duncan, 1876:431 [= Peponocyathus).
Levipalifer orientalis Vaughan, 1900:201-202, pi. 16: figs. 3-7 [junior