the echinoid fauna from japan and adjacent regions part i

222 s. NISIYAMA
A. AGASSIZ, 1881-a, p. 108,(partim), pI. lOa, figs. 1-2 (Japan, off Kobe, 8-50 fathoms; non
Agassiz, 1841). =Temnotrema sculptum A. AGASSIZ, 1863-a, p. 358.
Non Temnotrema POMEL, 1883, p. 87.-LAMBERT and JEANNET, 1935, p. 6.
Haplotype.-Temnopleurus hardwickii (GRAY) A. AGASSIZ, 1872-74, pp. 166, 460, pI. 8a, figs.
1-3 (Recent; Japan).
Test small, usually less than 20 mm in horizontal diameter, or very small, exceptionally
of medium size, usually thick and strong; low hemispherical or almost
globular. Podial pores in a straight or slightly undulating series, rarely with a
tendency to a biserial arrangement, usually not widened at the peristomial region.
Primary tubercles not, or only faintly, crenulate, often with the base more or less
distinctly stellate, indented by depressions on the plates; secondary tubercles more
or less developed, sometimes forming horizontal rows on the ambital plates, but
generally smaller than the primaries. Horizontal interambulacral sutures with a deep
pits at each end, of varying size, but in most species large and conspicuous. In the
ambulacra a pit at the median end of the sutures well developed; the pits generally
covered by a delicate membrane with a central hole. Apical system dicyclic; periproct
with a distinct suranal plate, sometimes nearly or completely covered by the
plate, the anal opening subcentral or pushed out to the posterior edge. Peristomial
membrane naked; buccal plates small, but distinct, each with a buccal foot, otherwise
naked, or with a few pedicellariae. Gill-slits very small. Spines short, rather robust,
smooth, usually terminating in a small knob, or very slender, slightly serrate, terminating
in a fine point. Globiferous pedicellariae with a lateral tooth on each side, or
without lateral teeth; poison glands double. Tridentate pedicellariae only exceptionally
found. Colour often very bright (after MORTENSEN, 1943).
From the Miocene to Recent.
The genus Temnotrema is clearly distinguished from Temnopleurus by its usually
non-crenulate tubercles (though only slightly crenulate in some large specimens of
Tem. sculptum), the uniform size of the spines, the uniform aspect of each sides of
the test as to tuberculation, and the presence of membrane with a central hole,
covering the pits. The beautiful and small-sized sea-urchins of this genus are confined
in the geographical distribution to the Indo-Pacific regions, exceptionally in the
Red Sea. Its occurrence in geological times dates back to the Miocene (Java and
Burma), but the record of Temnotrerna (as Dicoptella) from the Redonian stage (late
Miocene) of Normandy is particularly noteworthy.
The history of this generic name was revised by the writer (NISIY AMA, 1936, pp.
122-124) and by MORTENSEN (1943, pp. 245-246), and there is no need of repetition
here.
Among the three groups distinguished in this genus, as suggested by authors
(MORTENSEN, 1904, p. 91.-NISIY AMA, 1936, p. 127), the third group, which comprises
only one particular form (Tern. doederleini MORTENSEN, 1904) is separated from the
Temnotrema as a distinct genus, Paratrema, by KOEHLER (1927, p. 90), it is characterized
by having only five buccal plates and five tube-feet in the buccal membrane,
and lacking anal plate. The other two groups are closely related each other in
possession of ten buccal plates and ten tube-feet in the buccal membrane, and in a
more or less distinct anal plate; but the groups differ from each other only in the