Molluscan Assemblages — OKUTANI 
77 
m; Pseudoliotia micans (A. Ad.), 290 m; Clath- 
ofenella reticulata (A. Ad.), 290 m; Mucron- 
alia subulata (A. Ad.), 290 m; Tonna luteo- 
stoma Kiister, 280 rn; Coralliophaga euginiae 
(Bernard), 280 m; Bursa bufonia (Gmelin), 
280 m; Conus sp. (identified as C. tone by an 
illustration in Niino’s paper). 
7. Insular Shelf around Hachijo Island 
MATERIAL: None is available here. 
EARLIER WORKS: Niino (1952) reported 13 
pelecypods and 3 gastropods from depths of 
115 and 200 m. 
SPECIES REPORTED BY NIINO: Barbatia ha- 
chijojimensis Hatai, Niino and Kotaka, 115, 200 
m; Area mauia takii Hatai, Niino and Kotaka, 
200 m; Tucetona sp., 200 m; Spondylus cruen- 
tus Lischke (S. anacanthusl ) , 115 m; Spondylus 
sp.; Lima lima L. 115, 200 m; Pycnodonta mu- 
sashiana (Yokoyama), 200 m; Pseudochama sp., 
200 m; V asticardium arenicolum ( Rve. ) ; Mere- 
trix sp., 115 m; Callista pilsbryi Habe, 200 
m; Venus sp., 200 m; Phalium sp., 115 m; 
Ocenebra adunca (Sowerby), 115 m; Conus 
sp., 115 m. 
8. Insular Shelf around Torishima Island 
material: Part of specimens collected by 
test fishing for Cor allium operated at a depth 
of 150-250 m. The material was examined by 
courtesy of Mr. Kurata. 
EARLIER WORKS: None. 
SPECIES IN THE present MATERIAL: Spon- 
dylus anacanthus (Mawe); Pycnodonta musa- 
shiana (Yokoyama); Plicatula muricata (Sow- 
erby); Notolimea sp. cf. tosana Oyama; Chama 
argent ata Kuroda and Habe; Tenagodus an- 
guinus (L.) ; Talopena lifuana (Pilsbry); Can- 
tharus sp. 
SIMILAR MOLLUSCAN FAUNA FROM SOME 
BANKS SOUTHWEST OF KYUSHU 
On the Pacific Ocean side of Japan, groups 
of submarine banks other than those mentioned 
above are scattered throughout the southwest- 
ern waters off Kyushu (Figs. 1, 3). These also 
are situated on the submarine rise of the vol- 
Fig. 3. Detail for II in Fig. 1. Dots indicate the 
biological stations for the R.V. "Soyo-maru” in Feb., 
1959. 
canic system on which the Osumi Group lies; 
this situation is quite similar to that of the Izu 
Banks. Hereafter, this second series of banks is 
tentatively called the Osumi Banks. The tops of 
these banks are usually at about 100 m, and 
they are isolated from the neighboring islands 
by depressions of about 200 m in depth. Their 
general features are similar to the Izu Banks 
in that they have submarine sediments of coarse 
sand and gravel which are coated by calcareous 
algae. Some rocks exposed at the sea surface are 
also found (e.g., the Uji Islets). 
Oceanographically, the two series of banks 
are decidedly exposed to similar conditions with 
respect to the Kuroshio Current, for the usual 
main axis of the current passes through the 
Osumi Straits as well as across the Izu Sub- 
marine Ridge. 
The occurrence of molluscan species revealed 
by the present survey is as follows: 
9. Off Takeshima Island 
At a depth of 210 m; dredged by the R.V. 
"Soyo-maru” on Mar. 5, 1956; sta. 114: 30° 50' 
N, 130° 28' E. 
Area mauia takii Hatai, Niino and Kotaka; 
