the echinoid fauna from japan and adjacent regions part i

276
S. NISIYAMR
Koehleraster LAMBERT and THIERY, 1921, p. 331.
Orthotype.-Echinoneus abnormalis DE LORIOL, 1883-a (as abnormis), p. 41, pI. 5, figs. 2-2d
(Mauritius).-MoRTENsEN, 1948-a, p. 80, pI. 12, figs. 20, 22 (South Sea Islands, Rotuma
and Hawaiian Islands).
Moderate-sized forms. Test ovoid, fairly strong. Ambulacra narrow, not petaloid
aborally; pore-zones very narrow, slightly sunken, straight; trigeminate ambulacral
plates of the echinoid structure, but the pores form only one straight series; each
pore-pair with a distinct peripodium throughout the ambulacrum. Apical system
compact; genital pores four; genital plates not separate. Peristome oblique, without
branchial slits; peristomial membrane densely covered with small plates; periproct
close to the peristome, of ovoid outline, covered with spine-bearing plates. Tubercles
imperforate, or perforate, non-crenulate, not arranged in vertical series in the adult;
glassy tubercles may be very numerous and conspicuous. Spines short, simple, straight,
with a small axial cavity. Pedicellariae, of the globiferous, tridentate, ophicephalous,
and triphyllous types. Sphaeridia placed along the tube-feet. Spicules of
the tube-feet in the shape of irregular rods; the tube-feet generally have a well
developed sucking disk (after MORTENSEN, 1948-a).
From the Oligocene to Recent.
Micropetalon pllrpllreum A. AGASSIZ and H. L. CLARK, 1907 (A. AGASSIZ and H. L.
CLARK, 1907 -a, p. 251.-WESTERGREN, 1911, p. 63, pI. 29, figs. 1-14, pI. 30, pI. 31, figs.
1-17), from the Hawaiian and Macclesfield Bank (MCl no. 4752), has been included,
by LAMBERT and THIERY (1921, p. 331), in Echinonells. But it differs from LESKE'S
genus in that the apical spstem with separate genital plates, and that the pores in
ambital region being rudimentary, without peripodia. The Cretaceous genus PaleoechinoneliS
GRANT and HERTLEIN, 1938 (GRANT and HERTLEIN, 1938, p. 105.-0rthotype-Pal.
hannai GRANT and HERTLEIN, 1938, p. 105, pI. 23, figs. 4-5-Upper Cretaceous
of Lower California) has a striking similarity to Echinoneus, but it differs from the
latter by having the podial pores arranged in arcs of three adorally. LAMBERT and
THIERY (1921, p. 331) have considered that the perforate tubercles of Ech. abnonnalis
(loc. cit.) (MCl no. 4097, from Hilo, Hawaii) are sufficient to erect for it a distinct
genus, Koehleraster. This procedure, however, is rejected by the later writers, by
the reason that the perforate tubercles (occur in Paleoechinoneus also) are to be expected
to occur in this surviving group of the Holectypoids. JACKSON (1922, p. 54)
mentioned records of Ech. cyclOSt01nllS, the type-species, to have occurred as fossil in
the West Indies in the Oligocene, Miocene, and Pliocene formations.
Echinoneus cyclostomlls LESKE, 1778
Echinoneus cyclostomus LESKE, 1778, p. 173, pI. 37, figs. 4-5.-DESOR, 1842, p. 43, pI. 6, figs.
13-15.-GRAY, 1855-a, p. 32.-DESOR, 1855-57(57), p. 197, pI. 27, figs. 1-3.-A. AGASSIZ,
1872-74, pp. 117, 550, pI. 14, figs. 6-8, pI. 14a, figs. 5-10.-DE LORIOL, 1883-a, p. 38, pI. 5,
figs. 3-6.-TOKUNAGA, 1907, pI. 17, figs. 1-2.-WESTERGREN, 1911, pp, 44-63, pis. 1-28.­
COTTREAU, 1913, p. 106, pI. 12, figs. 1-2.-H. L. CLARK, 1917, p. 101.-JACKSON, 1922, p. 54,
pI. 9, figs. 1-2, 4-5.-H. L. CLARK, 1925, p. 177.-H. L. CLARK, 1926-a, p. 191.-H. L. CLARK
1945, p. 321.-HAY ASAKA, 1948, p. 26, pI. 6, fig. 2.-MoRTENSEN, 1948-a, p. 75, pI. 1, figs. 14,
26, pI. 12, figs. 21, 23.-TOKIOKA, 1953, p. 146.-UTINOl\II, 1954, p. 351.-COOKE, 1954, p. 46,
pI. 9, fig. 6.-MoRISHITA, 1964, p. 278, pI. 14, figs. 6-8.
Echinoneus abruptus H. L. CLARK, 1925, p. 177, pI. 10, figs. 1-3.