the echinoid fauna from japan and adjacent regions part i

236 S. NISIYAMA
a
Fig. 20. Javanechinus erbi J EA N NET, 1935 ( for comparison).
(Miocene of J ava and Madura Is lands) .
a. A part of the adoral s id e, x S.5 (after J EA NN ET, 1935).
b. Apical system (al l oculars excluded from the periproct) (after J EANN ET and
R. M ART IN, 1937).
jacent regions, but is represented by the following genera, viz., Prionechinus A.
AGASSIZ, 1879, Brochopleurus FOURTAU, 1920, Desmechinus H. L. CLARK, 1923, Printechinus
KOEHLER, 1927, and Lamprechinus DOOERLEIN, 1905.
There is a species of the genus Brochopleurus in our collection.
Genus Brochopleurus FOURTAU, 1920
Brochopleurus FOURT AU, 1920, p. 25.- L AM BERT and THIERY, 1925, p. 570.- M oRTE NS EN,
1943, p. 354.- T ERM IER and T ERM IER , 1953, p. 90S.- COOKE, 1959, p. IS.
Orthotype.- T emnechinus stellulatus DU NCAN and SL ADE N, lS85- a , p. 304, pI. 47, figs. 8- 9
(Miocene of Western India).
Javanechinus J EANN ET in L AMBERT and J EANN ET, 1935, p. 49.- J EAN NET and M ARTI N, 1937,
p. 235.
Orthotype.-Javanechinus rembangensis J EA NN ET in L AMBE RT and J EAN NET, 1935, p. 50,
text-figs. 66- 68, pI. 2, figs. 35- 37, pI. 4, figs. 17- 18 (Lower Miocene; Rembang, Java).
Graphipleurus H. L. CL ARK, 1945, p. 315.
Orthotype.- Graphipleurus g ranularis H. L. CL ARK, 1945, p. 315, pI. 41, figs. F-G (Lower
Miocene; F iji Islands).
Small forms of hemispherical shape. Ambulacra with trigeminate plates of the
echinoid structure; pore-pairs in a nearly straight line. Primary tubercles noncrenulate,
in regular series in both areas, and imperforate; a distinct radiating
sculpture from around the primary tubercles and partly also from around the secondaries.
A pical system (as far as known in the species) regularly dicyclic ; peristome
small, with small and indistinct gill-slits. Spines and pedicellariae unknown.
Miocene of India, East Indies, Egypt, A ustralia, and Fiji Islands, and the Lo\ver
Pliocene of Japan.
It seems evident that this extinct genus is so closely rela ted to the extinct
genus Ja vanechinus that the two genera may in all possibility, be identical with
each other, especially with regard to the sculpture of the test, shallow and indistinct
gill-slits, and the structure of apical system; i. e., it is known in the species Br.
b