a -lt"~±~~~ -.
-~·ic.f

Transactions and Proceedingsof thePalaeontological Society of Japan
New SeriesNo. 13

Palaeontological Society of Japan
June 15, 1954

CONTENTS
7RANSACTIONS'242. On the Miocene Pectinidae from the Environs of Sendai; Part. 4.

Pecten akitanus YoKOYAMA and Chlamys ttisataiensis OriJKA .............. .
... ... .. . ... ... ... ... ... ... ... ... ... ... ... ... ... .. . ... ... ... ... .. . ... .. . ... .. . ... Koichiro MAsuoA 111
243.

Notes on Some Tertiary Plants from Korea (Tyosen). III ................. .
... ... ... ... ."....................................................................... Kazuo HuztoKA 117

244. Electron-microscopic Fine Structure of Fossil Diatoms. I .................... .
.. . ... .. . ... ... .. . ... ... ... ... ... ... .. . ... ... .. . ... .. . ... .. . ... .. . ... ... ... ... ... .. . Haruo 0KUNO 125

245. Recent and Fossil Species of Brissus from Ryuku............................. .

... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .. . ... ... ... ... Akira MoRISHITA 131
PROCEEDINGS .................... .'..................................................................... 124

President:

Hisakatsu YABE

Councillors:

Kiyoshi AsANo, Riuji E:mo (Business and Accountant), Seido

ENDo, Haruyoshi FuJIMOTo,

Shoshiro

HANZAWA, lchiro HAYASAKA,

Nobuo lKEBE, Teiichi KoBAYASHI (Editor), Jiro MAKIYAMA, Tatsuro
MATsuMoTo, Tsuneteru OINOMIKAoo (Publication), Tokio SmKAMA,
Koiti SuzuKI, Fuyuji TAKAI (General Affairs), Hisakatsu YABE.

All Communications relating to this Journal should be addressed to the
PALAEONTOLOGICAL SOCIETY OF JAPAN
Geological Institute, Faculty of Science, University of Tokyo, Japan

Trans. Proc. Palaeont. Soc. japan, N.S., No. 13. pp. 111-116. Pl. 12, june 15, 1954

242. ON THE MIOCENE PECTINIDAE FROM THE ENVIRONSOF SENDAI; PART 4. PECTEN AKITANUS YOKOYAMAAND CHLAMYS NISATAlENSIS OTUKA.*
KOICHIRO MASUDA
Department of Geology, College of Education. Tohoku University, Sendai.

ftlli'lHJ'ili:rl•:tli*'tilff Pectinidae, ~ rD 4. Pec'en akita11us YoKoYAMA Ji.V: Chlamys
11isataiensis OTUK A f;::f'.tlf·-.:: : Pecten aki/a11us YoKoYAMA };!; !F Chlamys nisataie11sis OTITKA
a: ~~?19tiit t... J1P. tt'f:a1:wt*. t.:;y,t~ • -c 11) ~JlH:.fT-::> i:: o iltUI#.--J'll>

Chlamys nisataiensis was first described by Y. Onn\A in 1934 from
Nisatai in Nisatai-mura, Ninohe-gun,
Iwate Prefecture, and also recorded by
the same author from Tate, Shiratori
and Takaba, which are three localitiesof the same formation and in the same
Ninohe-gun. The formation from where
the species was originally described wasstated to be the Lower Kadonosawa
Series, a name which is not appropriate
from the standpoint of stratigraphicalnomenclature, and was therefore renamed by K. HATAI as the Shiratori
formation ; this is of Miocene age.
That the characters of the above
mentioned two species arc confusing
may be easily understood from the factthat Chlamys nisataiensis, although firstdescribed in 1934, was previously recorded as Pecteu akitames YoKOYAMAin 1933 by the same author. Similarlyin the environs of Sendai, H. MATSUMoTo
in 1929 recorded Pecten akitames
YoKoYAMA from Kumanodi> in Takadatemura, Natori-gun, which is a typicalfossil locality of the Moniwa formation.
However, there is no subsequent recordof that species from the Moniwa forma·tion, although S. NoMURA in 1940 re-

Introduction and Acknowledgements

Among the fossil scallops hitherto
recorded from the Miocene formations
developed in northeastern Japan, Pectetz
andChlamysakitmzus YoKoYAMA
11isataiensis 0TUKA are of particularinterest because of their confusing
dutracters and restricted geologicalrange as to be discussed in the following pages.
Pecten allitmms was first describedby M. Yoi\OYAMA in 1926 from Kurosawa
in Taihei-mnra, Minami-Akita-gun, alocality which is referred to Beds B ofK. MuRAYAMA, who collected the specimens. This species is also recorded by
M. YoKoYAMA (1926) from Kinonezaka
in Yazawagi-mura, Hiraga-gun, both in
Akita Prefecture. Kinonezaka is referred to Beds F of K. MuRAYAMA, whocollected the material. Of these mentioned Beds, the first one is considered
as belonging to the Wakimoto formationand the latter to the Sugota formation,
being Pliocene and Miocene in age respectively.

*Read Feb. 28, 1953; received March 27, 1953.

111

Koichiro MASUDA

112

ported on the occurrence of Pecten(Chlamys) 11isataiensis (OTUKA) fromboth Goishi and Kita-Akaishi, which are
two localities of the Moniwa formation.
The writer has also made extensive col·lections from the Moniwa formation at
the above mentioned three localities
and has failed to collect Clzlamys
alzitmza, thus suggesting that the species
has either been mis-identified or is very
rare.
Having studied the rich collections in
the Institute of Geology and Paleontology, Tohoku University, and in the
Saito Ho-on Kai Museum, both inSendai, and also those now preserved in
the Department of Geology, College of
Education of the Tohoku University,
the writer, herein, describes the characters of these two confusing scallops.
Acknowledgements are due to Dr.
Kotora HAT AI of the Departmentof Geology, College of Education, Tohoku
University, for kindly supervising thepresent work. Thanks arc also due to
Dr. Kiyoshi AsAso of the Institute ofGeology and Paleontology, Tohoku University, for his kind offer of the specimens which he collected from Kitano in
Yazawagi-mura, Hiraga-gun, Akita Prefecture, a typical locality of the Sugota
formation.

Family Pectinidae
Subfamily Pectininae
Genus Chlamys (BoLTEN) RoniNG, 1798

Chlamys allitana (YoKoYAMA), 1926
Pl. 12. Figs. 8a-b, 9a-b, 10, 11, 12a-b,
13a-b, 14, lSa-b, 16a-b. 17
1926 Pecl1'11 akitanus YOKOYAMA. four. Fac.
Sci., Imp. Ut~iv. Tokyo, Sec. 2, vo/. .9, p.
388, pl. 44. figs. 15. 16, 17.

The original description of Pecten
akitamts is as follows :·• Shell small, rather thick, compressed,
orbicular, somewhat higher than long,radiately ribbed.
Right valve: Ribs about twenty-fivein number, flattened, usually broader
than interspaces, often split into two by
a groove; ears unequal, with radiately
riblets, anterior longer and larger thanposterior, byssal notch triangular.
Left valve : Of about the same convexity as the right valve, ribs about
twenty-five, but with an intercalarly inevery interspace, occasionally splitting
into two like those of the right valve;ears unequal, with posterior larger,
radiately ribbed. "The present specimens which are
typical, take the following description.
Shell small, rather thick, suborbicular,
subequivalve, equilateral except for·auricles and radiately ribbed. Right
valve with 23-25 round-topped, radialribs and concentric growth lines, tjnd
rarely with intercalarly threads; finely
imbricated ; radial ribs usually bifurcate
at about half of disc-length and broader
than the interspaces; the bifurcatedradials subcqual in strength near margin. Left valve with 23-25 round-topped, radial ribs, intercalary thr~ads andfine concentric growth lines making surface finely imbricated ; radial ribs rarely
bifurcate and as wide as or narrower
than the interspaces; intercalary threads
subequal in strength near margin in
adult specimens. Anterior auricle ofright valve larger than posterior, with
distinct byssal notch, narrow byssal
area and distinct ctenolium ; auricles
sculptured with radial threads and concentric lines by which they appear
imbricated. Auricles of left valve subequal and sculptured with distinct radial
threads and concentric lines, and alsoOn the Miocene Pcctinidae from the Environs of Sendai.

imbricated; anterior with wide andshallow byssal notch. Hinge straight,
cardinal crura of right valve rather
distinct, and lateral ridges of resilial
pit widely open towards the lower.
Internal surface rather smooth, butwith marginal serration.
Remm·ks.-This species is characterized
by the rather thick and small shell
which is provided with 23-25 roundtopped, dichotomizing radial ribs rarely
with intercalary threads on the rightvalve, and by having 23-25 round-topped,
rarely dichotomizing radial ribs withintercalary threads on the left valve.
The right and left valves are nearly
equal in convexity.
Pecten (Chlamys) jordatzi ARKOLD(1906, p. 114, pl. 44, figs. 1, la, lb) fromthe Pliocene and Pleistocene formationsof California, resembles allitana inhaving numerous, smooth topped, imbricated, dichotomizing radial ribs.
ARNOLD's species is distinguishable fromakitana by the larger and rather thinnershell, by being inequi;•alve and by thenarrower and deeply channeled interspaces.
Dimensions (in mm).Valve

Right Right Right Left LE>ft Left

I

Height

20

18

14

32

18

25

Length

19

17

14

31

17

24

Hingelength

10

9.5

8

15

10

11

Depth

5

4

3

g

4

6

Apical

goo

g5°

95°

gso

go' goo I-~!lgl_e

I

I
I
I

Type locality and geological formation.Road cliff near Kurosawa, Taiheimura, Minami-Akita-gun, Akita Prefecture. W akimoto formation. Pliocene.
(There are no subsequent
records of collections of this species
from the type locality. The writerPart 4.

113

feels that Kinonezaka in Yazawagimura, Hiraga-gun, Akita Prefecture(Sugota formation) may be the true
type locality and geological horizon of
the species.)
Described sPecimens.-Kitano, Yazawagimura, Hiraga-gun, Akita Prefecture.
Coarse grained sandstone of the
Sugota formation (Miocene). Collectedby Dr. K. AsAKo and now preservedin the Department of Geology, Collegeof Education, Tohoku University.

Chlamys nisataiensis 0TUKA, 193!
Pl. 12, Figs. la-c, 2. 3a-b, '1·, 5, 6. 7

1g34 Chlamys islmzdicus nisataieusis OTUKA.
Bull. Earthq. Res. Imt .. Imp. lhziv., Tokyo.
vol. 12, pt. 3. pp. 612-613. pl. 47, fig. 26.
19•W Pecle11 (Ch/amys) nisalaie11sis (OTUI<A).
Nol\IURA, Sci. Rep., Tohoku Imp. Unit! ..
Ser. 2. rol. 21. no. 1, p. 18. pl. 2. figs. 5.
6.

The original description of this species
is as follows :" Shell moderate in size, the heightalmost equal to the length, subequivalve
and subequilateral except for the ears,
rather thin, compressed, radially costate.
Beaks small, sharply pointed, approximate. Ears unequal, the anterior large,
triangular, that of the right valve witha deep byssal notch ; the posterior
triangular, truncated behind at rightangles or obtuse. Discs right angled
above with the dorsal margin descending
slightly concave meeting with the regularly rounded ventral margin at broad
angles. Left valve more or less inflated
than the right which margin is crenate.
Sculpture : anterior of left valve with
about 6-12 unequal scaly radial riblets(12 in the paratypc of the left valve),that of the right valve divided into theupper area with flexuose, lamellated,horizontal, incremental lines; posterior
ears with 6 to 12 low scarbrous riblets,

114

K6ichir6 MASUDA

which interspaccs with a feeble riblets;
the riblet obsolete near the upper
margin; discs with 30 to 33 subequal,
equidistant, flat-topped, roundly edged
ribs which are dichotomous at its ventral part (they show the dichotomous character after reaching a heightof about 30 mm.); interspaces aswide as or a little narrower than theribs, usually with an intercalating
riblet; except for the posterior andanterior part. The posterior anrl anterior part densely ·ribbed, and the intercalating riblets obsolete. Incremental
lines very fine, not much imbricated.
Interior side obscurely radially grooved.
Ventral margin strongly crenated".
The specimens collected from the
Moniwa formation at Goishi in Oidemura, Natori-gun, Miyagi Prefecture
take the following description.
Shell small, rather thin, compressed,
suborbicular, subequilateral, subequivalve, though the left is a little more convex
than the right ; radiately ribbed. Right
valve with 25-32 flat-topped, somewhat
square, radial ribs and intercalarly
threads ; radial ribs usually bifurcate at
the lower half of disc length and usually
as wide as or a little narrower than theinterspaces at the upper half of disc,but tend to become broader than theinterspaces with growth ; intercalarythreads-appear at about same time as
or a little earlier than rib-bifurcation,and subequal to bifurcated radials instrength at margin in adult speCimens.
Left valve with sculpture similar tothat of right. Anterior auricle of rightvalve larger than the posterior, andwith conspicuous byssal notch. narrow
byssal area, and distinct ctenolium : theauricles sculptured with rather distinct
radials and concentric lines, by which
they- appear somewhat imbricated. Anterior of left valve larger than theposterior which is provided with ashallow byssal notch, and of sculpture
similar to that of right valve. Cardinal
crura of right very distinct; latera\ridges of resilial pit distinct and withwide opening towards lower p:ut. Internal surface of valves rather smooth
except for marginal serration.

Dimensions (in mm).Valve

Right Right Right Left Left Left ~Height

30

22

19

24

23.5 21

Length

29

21

17

23

22

20

Hingelength

Itf.

10

11

10

11

Depth

4

3

3

4

4

3.5

Apical
angle

goo

goo

goo

95°

90' I

Remarks.-This species is characterized
by the rather thin, small, rather compressed shell which is provided with
25-32 flat-topped, dichotomizing radialribs, by the intercalary threads and by
the right valve being less convex thanthe left one. The ribs are usually narrower than the interspaces on the upper
half of the disc, but rarely the interspaces are narrower than the radial ribs.
The relationship between radial ribs andtheir intersp:1ces is not const:mt.
Cltlamys akitana (YoKOYAMA) described in the earlier pages is very close
to the present one, but can be distinguished from nisataiensis by the rather
thick shell, subequal convexity of thevalves, fewer number of radial ribs, by
the radials being broader than theirinterspaces, and by the rare intercalarythreads of the right valve as well as by
the rare bifurcation of the left valve.
The cardinal crura of this species ismore distinct than in akitana.

Pecten ( Chlamys)
mentionedinjordani

earlier pages,

ARI'oLD,isalso

On the 1\Iiocene Pectinidae from the Environs of Sendai.

related to uisataienst"s, but is distinguishable by the larger shell, muchlarger anterior auricle, and by the
deeply channeled and narrower interspaces.
Geological si'gnificance. - The rocks
from where Chlamys akitana (YoKoYAMA) has been collected or reported byauthors comprises sandy siltstone as at
Kurosawa, Taihei-mura, Minami-Akitagun, Akita Prefecture, which is said tobe the type locality of the species ; thisis the W akimoto formation, granuleconglomerate as at Kinonezaka, Yazawagi-mura, Hiraga-gun in the same
Prefecture; this is the Sugota formation,coarse-grained sandstone as at Kitano,
Yazawagi-mura in the same district andPrefecture; this is the Sugota formation,coarse-grained, tuffaceous sandstone as
at Kumanodi>, Takadate-mura, Natorigun, Miyagi Prefecture; this is the
Moniwa formation, and of green tuff asin the Kunnui formation in southwestern
Hokkaiko as r-:ported by T. NAGAo and
Y. SASSA.
Chlamys uisataiensis OTUKA occurs informations consisting of co<,rse·grainedsandstone as at Nisatai, Nisatai-mura,Ninohe-gun, Iwate Prefecture; this is
the Shiratori formation, and of gr~nuleconglomerate or of impure limestone as
at Go'shi and Kita-Akaishi, Oide-mura,
Natori-gun, Miyagi Prefecture.
The conditions of the sea bottom on
which the above mentioned two scallops
once lived can be understood from thenature of the rocks which now preservethem. The thermal conditions of thesea at the time of the building of the
Moniwa, Sugota, Shiratori and Kunnui
formations is judged by the associatedfauna of the two scallops, which comprise bivalves, univalves, echinoids andforaminifers of tropical to subtropicalaspect. From the available data it isPart 4.

115

evident that the two scallops lived in
the neritic zone upon a bottom freefrom mud derived from the land andunder the influence of very mild thermal conditions.
Although_ the type locality of Chlamys
akitmza (YoKoYAMA) has been ascribedto the Wakimoto formation at Kurosawa,
Taihei-mura, Minami·Akita-gun in Akita
Prefecture, it is also evident that there
are no subsequent records nor collectionsof the species from that locality, andthat it is common in the Sugota fonnation and its correlatives. Accordingly,
the writer feels that the locality ofKinonezaka, Yazawagi-mura, Hiragagun, Akita Prefecture (Sugota formation) is the true type locality and thatthe possibility of some mistake cannot
be overlooked.
If the afore-mentioned statement concerning the type locality of Ch!amys
akitana ( YoKoY Al\IA) proves to be as thewriter now feels, it follmvs that both
Chlamys akitana(YoKoYAMA) andCltlamys tzisataiensis 0TUKA are restricted in their geological range toearly Miocene, or more precisely to
Lower and Middle Miocene.
References
R. (1906), Tertiary and Quaternary
Pectens of California. Prof. Paper, U. S.
Geol. Surv., No. ·17, p. 114, pl. 44, figs. 1,
la, lb.
HATAI, K. and S. NJSIYAMA (1952), Check
List of Japanese Tertiary Marine Mollusca.
Sci. Rep., Tohoku Univ., Ser. 2, Spec. Vol.
No. 3, p. 106.
!VlATSW.lOTO, H. (1930), On the Marine
Faunae of Three Fossil Zones of theUpper Miocene of Natori District, Provinceof I~ikuzen. Sci. ReP., Tohoku Imp. U11iv ..
s·er. 2, Vol. 13, No. 3, p. 104.
NAGAO, T. and Y. SASSA (1934), On the
Cenozoic Formations and its Recent His-

ARNOLD,

116

Koichiro MASUDA

tory of Southwestern llol<kaido.
four.
Geol. Soc. 'Japa11, Vol ..J /, No. 488.
Nol'\IURA, S. (194.0), 1\Iolluschn Fauna of the
Moniwa Shell Bed Exposed along theNatori·gawa in the Vicinity of Sendai,
Miyagi Prefecture, Japan.
Sci. Rep.,
Tolzoku Imp. Utriv., Scr. 2, Vol. 21, No. 1.
OTUKA, Y. (1933). Stratigraphy of the Vicinityof Fukuoka·machi and lchinohe-machi,
Ninohe-gun, Iwate Prefecture. Jour. Ceo/.
Soc. Japan. Vol . .JO, No. 475.
- - (1934), Tertiary Structures of the Nor·theastern End of the Kilakami Mountain·
land. Iwate Prefecture, japan.
Bull.
Earthq. Res. h1st., Tol1yo Imp. lf11iv., Vol.
12. No.3.
- - (1936), The Takasegawa Green Tuff Bedsof the Yuri District, Akita Prefecture.
Japan and Correlation of the Lower
Neogene in Japan. Bull. Earthq. Res.
Inst .. 1'okyo Imp. Univ., Vol. 14, No. 3.
YABE, H. and K. HATAI (19·tl). The Cenozoic

Formations and Fossils of Northeast
HonsyO, Japan. Sci. Rep., Tohok11 Imp.
Univ., Ser. 2,. Vol. 22, No. 1.
YOIWYAI\IA, M. (1926), Fossil Mollusca fromthe Oil-Field of Akita. four. Fac, Sci.,
Imp. U11i1•. Tokyo, Sec. 2, Vol. 1, Pt. 9.
p. 388, pl. 44, figs. 15, 16. 17. (Typelocality and holotype of Chlamys akitana
not designated. K. HATAI and S.
NISIYAI\IA, designated "Kurosawa, Taiheimur<~,
Minami-Akita-gun, Akita Prefec·ture" as the type locality. M. YoKOYAMA's
figures 15, 17 represent left valves andfigure Hi a right valve. Here the writerdesignates figure 16, as the holotypc ofChlamys akilana (YoKOYAMA). Depository of the holotype and paratypes is notstated in M. YoKOYAMA's work, but K.
HAT AI and S. NISIYAI\L-\ state "Geological Institute, Tokyo University" withquestion).

Explanation of Plate 12
Figs. la-c. Clz!amys nisataicnsis 0TUKA, a, Right valve, x 1. b, Inner surface, x 1, c, A part ofouter surface of b, x 3. Loc. River floor of Natori River 200 m. downstream from Go;shiElectric Power Plant. Oidc-mura, Natori-gun, Miyagi Prefecture.
Fig. 2. ChJamys nisalaicnsis OTUKA, Right valve, x 1, Loc. Same as above.
Figs. 3a-b. Chlamys nisataiensis OTUKA, a, Right valve, x 1. b. Hinge area of 3a, x 3, S:~me Loc.
Fig. 4. Ch/amys nisataiensis OTUI<A. Left valve, x l. Loc. Same as above.
Fig. 5. C!zlamys nisataicnsis 0TUKA. Left valve . x 1, Loc. Same as above.
Fig. 6. Chlamys 11isataiensis OTUKA. Left valve. x 1, Loc. Same as above.
Fig. 7. Hinge area of Clzlamys nisataiensis OTUKA, Left valve, x 3. Loc. Same as above.
Figs. Sa-b. Chlamys akitmltl (YoKOYAMA). a, Right valve, x 2, b, Inner surface of Sa, x 2, Lac.
Kitano, Yazawagi·mura, Hiraga-gun, Akita Prefecture.
Figs. 9a-b. Chlamys akilana (Yol<oYAMA), a, Right valve, x 2, b. Inner surface of 9a, x 3, Loc.
Same as above.
Fig. 10. Chlamys akilana (YOKOYAMA), Right valve, x 2, Loc. Same as abave.
Fig. 11. Ch/amys akitana (YoKoYAMA), Right valve, x 2, Lor. Same as above.
Fig. 12a-b. Chlamys akitmlfl (YoKOYAMA), a, Right valve. x 3, b, Hinge area of 12a. x 3, ditto.
Figs. 13a-b. Chlamys akita11a (YoKOYAMA), a. Left valve, x 3. b, Hinge area of 13a, x 3, ditto.
Fig 14. Inner surface of Chlamys akitana (YOKOYA:O.!A), Left valve, x3, Loc. Same as above.
Figs. 15a-b. Chlamys akitmw (YoKoYAl\1A). a. Left valve, x 2. h. Inner surface of 15a, x 2, ditto.
Figs. 16a-b. Chlamys akitrma (YoKoYAMA), a, Left valve. x 1, h. Inner surface of 16a. x 1, ditto.
·Fig. 17. Chlamys akitana (YOJ\OYAMA), Left valve, x 2, Loc. Sim1e as above.

MASUDA : Miocene Pectinidae

K. Ku MAGAI, Photo.

PLATE 12Trans. Proc. Palaeont. Soc. Japan, N.S., No. 13, pp. 117-123, Pl. 13, June 15, 1954

243. NOTES ON SOME TERTIARY PLANTS FROM KOREA(TYOSEN). III
KAZUO HUZ10KA!\lining College, Akita University?Ut-~~~fi!;filf~1t7i lii:;.$: l.~"t?l.t!Olif-4~ ljl~t!t Betulaceae v 7 -1:> Betula 2 f,Y,
CarjJillttS 5 f.lll, Ostrya 1 f!R5:1i~iftiGLtc 0 Altius il;it:'f.4?btvt-'1v?1c.<IJi;J:t.rL...~:(.)',n"t:;t?> 0

itill£4-.'JJ

MioctneContents

beds of~ankyo Do (ENJ..>O,

Keirin coal-mine, N.
1950, p. 51. Pl. 6, Fig.

1).

Genus Betula: Betula myongchonensis, sp. nov.
and B. shiragica, sp. nov.
Genus Carpinus: CarPinttS carjJinoides MAKINO,
C. erosa ellijJticibracteata liiJZIOKA, C.
Kodairae-bracteata HUZIOKA, C. miocordata
llu et CHANEY. and C. simp/icibracteata
IIUZIOKA
Genus Ostrya : Ostrya shiragimw, sp. nov.

C. erosa BLUME elliPlicibracteata HUZIOKA
Kantindo formation of N. Kankyo Do(HUZIOKA. 1943b. p. 290).
C. hokoensis ENDO
Enniti series of Hoko, N. Keisyo Do (ENDO,
1950. p. 55. Pl. 6, Fig. 10).
C. Kodairae-bracteala HUZ!OKA
Engellzal'dtia bed of N. Kankyo Do(HUZIOKA, 1943b, p. 290, Pl. 14. Figs. 14.
15, 15a).
C. kyttShinensis Erma
Miocene beds of Kyushin coal-mine, N.
Kankyo Do (ENDO. 1950, p. 53, Pl. 6. Fig.
7).
C. jJro/oerosa TANAI
Enniti series of N. Keisyo Do (T AI'AI,
1952, p. 232. Pl. 22. Fig. 2).
C. Pmtojaponica ENJ..>O
Miocene beds of Kyushin coal-mine, N.
Kankyo Do (ENDO, 1950, p. 52, Pl. 6, Figs.
3, 5); Enniti series of N. Keisyo Do (T ANAl,
1952. p. 231. Pl. 22, Fig. 1).
C. rancanensis IIAYATA
Miocene beds of Kyushin coal-mine, N.
Kankyo Do (ENDO, 1950. p. 52, Pl. 6, Fig.
4).
C. simplicibracteata HUZIOKA
Enniti series of N. Keisyo Do (HUZIOKA.
1943b, p. 290, Pl. 14, Figs. 13, 13a).
C. spp.
Kantindo formation (ENDO, 1938a, name

Fossil species of Betulaceae hitherto
reported from Korea are as follows :Betula cfr. Ermmmi CHAM.
Kantindo formation cf N. Kankyo Do(TATEIWA, 1925, name only).
B. spp.
Kantindo formation of N. Kankyo Do(TATEIWA. 1925. name only); Engellwrdtia
Bed of N. Kanl<Yo Do (ENDO, l938a, nameonly).
Carpinus carpinoides MAKINo (=C. japonica
BLUME) Kantindo formation of N. Kankyo
Do (ENDO, 1939. p. 340. Pl. 23. Figs. 3. 4);
Enniti series of N. Keisyo Do (KANEHARA,
1939, name only).
C. cuspidata SAPORTA
Enniti series of N. Keisyo Do (KA="EHARA,
1936, name only).
C. erosa BLUME (=C. cordata Br.UME)
Read May 13, 1953 ; received May 13, 1953.
117

Kazuo HUZIOI\A

118only) ;md Enge/hardtia bed (ENDO, Hl38a,
name only) of N. Kankyo llo.

In the present paper, the writer described the following species of Betulaceae
from the l\•liocene floras of Korea :Betula myongchonensis, sp. nov., B.
shiragica, sp. nov., Carpinus carpinoides
MAKINo, C. erosa Br.u.ME elliPticibracteata
HuzioKA, C. 'miocordata Hu et CHANEY,
C. Kodairae-bracteata HuziOKA, C. sim·
Plicibractcata HuzroKA, and Ostrya shi·ragiana, sp. nov.
Betulaceae are one of the most domi·
nant families in the modern forests of the
Korean peninsula, containing five generaof Alnus, Betula, Carpinus, Corylus andOstrya, Betula and Carpinus, each ofthem bears many species and varieties
respectively, are living almost in thewhole peninsula. Ostrya japonica SAR·
GENT, single species of the genus in
Korea, grows merely in the most southern part of it.
Description of Species

Betula mymzgclwnensis, sp. nov.
Pl. 13. Figures 1-2

Description :-Leaf ovato-elliptic toovato-oblong, 6-10cm long and 2.5-4.0cm
broad, acuminate at the apex, roundedat the base. Margin cornpoundly serrate.
Mid vein thick and straight to the apex;
lateral veins 11-13 pairs in number,straight to the marginal teeth, leaving
the midrib at angles of about 40°; someweak tertiary veins branched from thelaterals at the marginal border to thesmaller marginal teeth. Petiole thick,L0-1.5 em long. Texture thin.
Comparison and remarlls :-The pre·sent species shows an apparent resemblance to Asiatic living species such as
B. costata T1muT., B. sol/ennis Komz.,
B.

alttoides

HAMILTON,

B. ·ittsignis

FRAKCJ 1., and B.Schmidti REGEL Above
all, it seems to be most related to B.
aluoidcs of Szechwan and Yunnan in
China.
B. myongchoncnsis, sp. nov., is distinguished by its more elongated leaf
from the allied European species suchas /3. attenuata GoPPERT ( 1855, p. 11, Pl.
3, Fig. 6), B. elliPtica SA!'oRTA (1867, p.
59, Pl. 5, Figs. 3, 4). and B. Brongniarti
ETTIKGsliAUSE~ (1851, p. 12, Pl. 1, Figs.
16, 18). B. vera BRowN (1937, p. 171, Pl.
48, Figs. 7-11) of the Spokane flora of
Washington is similar to our specimens
in the elongate shape of leaf, excepting
its slightly cordate base.
OccurreiiCC :-Yutendo, Meisen-gun, N.
Kankyo Do ; Ryudo formation (Miocene); Coli. S. OisHI.

Betula shiragica, sp. nov.
Pl. 13. Figures :3-,lDescription :-Leaf rhombic ovate orovate, generally large, 7.0-115 em longand 4.0-6.5 em broad, acuminate at theapex, broadly cuneate at the base,irregularly duplicato-serrate at the margin. Midvein thick and straight to theapex; lateral veins equidistantly ar·ranged, almost constantly 11 pairs in
number, diverged from the midvein atangles of about 45°, straight or slightly
up-curved to the marginal teeth, moreor less decurrent at their bases; tertiaryveins weak, leaved from the laterals at
the marginal border to the smaller
teeth; finer veins percurrent, forming
minute reticular and polygonal meshes.
Petiole rigid, about 1.5cm long. Texture
seems to be somewhat thick.
Comparison and remarks :-In generalappearances, the present fossil resembles
Betula glohispica SmRAI in Central
Japan, but differs from it in the moreelongated shape of leaf and the incon·

Notes on Some Tertiary Plants from Korea (Ty6sen).

spicuous teeth at the leaf margin. This
Korean species may be essentially similar to B. macroplzylla (GoPPERT) HEF.R
CGoPPERT, 1855, p. 12. PI. 4. Fig. 6; Pl.
5, Fig. 1, as Altzus macrophylla) and B.
grmtdzfolia ETTINGSJIAUSF.:-1 (1866, p. 47,
Pl. 14; Figs. 23, 24), but is distinguishable from them in having smaller marginal teeth, many lateral veins, andremarkable cuneate base. B. miolumi·
11ijera Hu et CHANEY (1940, p. 30, Pl. 5,
Figs. 5, 6: Pl. 7. Figs. 1, 2, 3; Pl. 9, Fig.
1) of the Shanwang flora in China andB. saclzalimmsis HEER (1878, p. 33, Pl. 6,
Figs. 1-3) from the Dui coal-bearing
formation of Sachalien also resemble
our species, but the former has arounded base and the latter has thelateral veins more densely arranged.
B. lucustris MAcGI:-;ITJE (1933, p. 50, Pl.
4, Figs. 2, 3, 4) of the Trout Creek florain the Western United States shows aslight similarity to our leaves.
Occurrence :-Kinkodo, Usen ·men, Gcizitu·gun, N. Keisyo Do, Enniti series(Miocene); Coils. KooAIRA and UoTANJ.

Carpinus carpinoides MAI\I~o(syn. <.:. japonica BLUME)
1936. Carpinus carpinoides, KANEHARA: p. 82
1938. Carpinus japonica, ENDO : p. 34·0, Pl. 23,
Figs. 3, 4Some of the Carpinus-leaves which
are almost unseperable from the existing
C. carpinoides MAKINO occurred at the.Enniti Miocene rocks. This species now
grows widely in Japan and its fossils
have been recorded from the Pliocene(MIKI, 19-ll) and Pleistocene (ENoo,1940) floras of Japan.
Very recently, involucres of C. protojaponica Er-mo which are very similar to
those of the living C. carfJi1toides werereported by E:-~oo (1950, p. 52, Pl. 6,

Ill

119

Fig. 2) from the Miocene beds of the
Kyushin coal-mine of N. I<ankyo Do
and by TANAI (1952, p. 231, Pl. 22, Fig.
1) from the Enniti series of N. KeisyoDo.
Occurrence :-Kinkodo, Usen-mcn, Geizitu-gun, N. Keisyo Do; Enniti series(Miocene), Colis. KoDAIRA and UoTAKJ ;Kantindo, Meisen·gun, N. Kankyo Do,
Kantindo formation (Miocene), Col!.
OISHI.

CarPinus erosa BLUJ\IE el/ipticibracteata
HuzroK\
194~lb.

CwjJinus crosa Br.UME c/lipticibracteata
Huzlm:A: p. 290. Pl. 14·, Figs. 6, 7. 7a.
8, t'a. 9, 9a.

The fossil bracteole found by E;;oo(1939, p. 339, Pl. 23, Fig, 5) from theKantindo formation is doubtlessly similar
to Carpinus erosa BLlJl\iE (syn. C.
cordata BLUME). In 1943 HuzwKA described C. erosa ellipticibracleata from
the Miocene Abura flora of IIokkaido
and included the Kantindo involucre in
his new subspecies. C. crosa elliPlici·
bracteata is very close to the modern
involucres of C. erosa in Asia but
generally oblong and elliptical in outline.
Occurrence :-Kantindo, Meiscn-gun, N.
Kankyo Do, Kantindo formation (Miocene).

Carpinus Kodairae-bracteata Huz1oKA
1943b. Carpinus Kodairae·bracteata ilUZIOKA:
p. 290, Pl. 14. Figs. 14. 15. 15a.

Description :-Involucre palmately trilobed.
The median lobe is the largest, lanceolate, acuminate at the apex,
coarsely serrate at the margin; lateral lobes small, trigonal, acuminate
at. the apices, slightly serrate at the

120

Kazuo HUZIOKA

upper margins. The base of the invol·
ucre rounded. About 10 nerves radiatefrom the base, slender in habit ; themedian vein straight to the apex of thebracteole, branching some lateral veinsat the way to the margin. Dimentionof the type specimen : 2.3cm high, 1.2cm
broad; stalk 4 mm long.
Comparison and remarks :-Of theliving Cm·pinus, C. laxiflora BLUME
which exists commonly in Northeastern
Asia is most related to this fossil, but
the living is much smaller, more roughly
serrate at the margin, and less crowded
in nervation. C. sllanwa11gensis Hu et
CHANEY (1940, p. 34, Pl. 12, Fig. 6) has
the trilobed bracteole which is morpholo·
gically similar to the present form.
Occun•euce :-Ryuhokudo, Kokangencoal-mine, N. Kankyo Do, Engellzardtia
bed (Miocene), Coils. KoDAIRA andUoTAKJ.

the smaller teeth ; finer veins weak,percurrent. Petiole unlmown. Texture
seems to be thin.
Comparison and remarlls :-The present specimens are quite identical with
Carpinus miocordata Hu et CHANEY of
the Miocene Shanwang flora, China. C.
miocordata is most closely comparablewith C. erosa BLUME (syn. C. cordata
Br.UME) of the temperate forests ofNortheastern Asia. Hu et CHANEY (1940)
distinguished this species from C. subcordata NATHORST (1883, p. 39, Pl. 2,
Figs. 13, 18, 20) of the Mogi flora, but
the morphological resemblance between
these two species is quite obvious, bothbeing closely similar to the living C.

eros a.
Occurrence :-Kinkodo, Usen-men, Geizitu-gun, N. Keisyo Do, Enniti series(Miocene), Colis. KooA IRA and UoTA:-<1.

Cm·piuus simplicibracteata HuziOKA
Carpinus miocordata Hu et CHANEY
Pl. 13, Figures 5-6
1936. Carpi IIttS subcordala, KANEHARA: p. 82.
1940. Carpinus miocon/ala HU and CHANEY :p. 31, Pl. 12. Figs. 1. 2, 11.

Description :-Leaf large, generally
7-9 em long and 4.0-4.5 em broad, thelargest one with 8 em width and longer
than 12 em, oval, ovato-elliptic or obovato-elliptic in outline, acuminate at
the apex, distinctly cordate at the base.
Margin densely and compoundly serrate,
but some seeming simply serrate; marginal teeth sharply pointed. Midvein
rigid, straight to the apex; lateral veinsparallel, eqidistantly arranged, straightor slightly up-curved to the marginal
teeth, 13-18 pairs in number, diverging
at angles of approximately 45° from themid vein; tertiary veins branched fromthe laterals near the margin to reach

1943b. Carpi11us simjJiicibracleata HUZIOKA: p.
290. Pl. 14, Figs. 13, 13a.

Description :-Involucre small, long
elliptic in outline, acuminate at theapex, bearing a pair of teeth at theapical margin, obtuse at the base.
Primary nerves three in number, radiatefrom the base of involucre ; the medianvein strongest and straight to the apex,
t11e lateral two end in the apical marginal teeth. Dimension of the type specimen : 1.7 em high and 0.65 em broad.
Comparison and remarks :-Apparently the present bracteole seems tobelong to the genus Ostrya, but thewriter referred it to the genus Carpinusby the presence of marginal teeth andthe characters of nervation. This typeof bracteole may belong essentially to
C. erosa group, though this is quite
curious in having the simple charactersby which this species is easily distin-Notes on Some Tertiary Plants from Korea (Tyosen). III

guishable from C. et·osa and C. et·osa
elliPticibracteata.
Occurrence :-Kinkodo, Usen-men, Geizitu-gun, N. Keisyo Do, Enniti series(Miocene), Colis. KonAmA and UoTANJ.

Ostrya shiragiana, sp. nov.
Pl. 13, Figures 7-8.

Description :-Leaf elliptic ovate, 7.07.5 em long and 3.5-4.0 em broad. Apex
acute, base broadly cuneate or cuneatoobtuse, slightly inequilateral. Margin
irregularly duplicato-serrate. Midvein
rather thick, straight to the apex ;lateral veins alternate or subopposite,parallel, straight to the marginal teeth,
11-13 pairs in number, diverging fromthe midvein at angles of 45°; somedistinct tertiary veins leaved from thelaterals near the margin to the marginal teeth ; finer veins obscure. Petiole
thick, about l.O em long. Texture seems
to be rather thin.
Comparisoll and remarks:- Three species of Ostrya, 0. japmzica SARGENT, 0.
Reltderiana CJWN and 0. Liaua Hu,
are now living in Eastern Asia. Amongthem 0. japo11ica is most widely distributed in Japanese Islands, southern
Korea and Middle China. In both of 0.
japonica and 0. Reltdcriana, the leaf iscaudato-acuminate at the apex and its
petiole is shorter than 1.0 em, and in 0.
Liana the leaf is generally cordate at
the base.
Four fossil forms of Oslrya have beenreported from the Japanese Neogene
Tertiary ; they are 0. japonica of the
Nenoshiroishi flora near Sendai (Ermo,l938b, p. 619) and the Heigun flora of
Yamaguti Pref. (HuzJOKA, 1938, p.
148), 0. virginica WILD. fossil is NATIIORSTof the Mogi flora (NATHORST, 1883, p.
42, Pl. 3, Fig. 2) and the Omi flora in

121

Nagano Pref. (KoN'No, 1931, Pl. 9, Fig.
2), 0. Knowltonii CoNVILLE (?) of the
Uchiyama flora in Nagano Pref. (ENno,
1933, p. 49, Fig. 10) and 0. japonica
oblongibracteata IluziOKA (19~3b, p. 289,
Pl. 14, Figs. 1, la, 2) of the Abura florain Hokkaido. The former two of them
are represented by leaves and the latter
two by involucres. 0. vz'rgitzica fossi!isof lVIogi may belong to the genus Ulmus
as already pointed out by ETTINGSIIAUSEN( 1883, p. 858 ).
In the general characters, leaves of
0. orcgoniana CIL\NEY (1927, p. 106, Pl.
9, Fig. 12) from the Bridge Creek floraof Oregon are closely related to thisKorean species. Another foreign similar
species is 0. oeningensis HEER (1856, p.
42, Pl. 73, Figs. 5-10) of the Swiss
Miocene flora though it is cordate at
the base.
Occurrence :-Kinkodo, Usen-men, Geizitu-gun, N. Keisyo Do, Enniti series(l\iiocene), Colis. KoDAIRA ancl UoTANI;
Yutendo, Meisen-gun, N. Kankyo Do,
Ryudo formation (Miocene), Coil. OISHI.
References
BIWWN. R. \V. (1937). Additions to Some
Fossil Floras of the Western United States
U.S.C.S. Prof. Paper. 186.].
CHANEY, R. W. (1927), Geology and Paleontology of the Crooked River. with Sp~cial
References to the Bridge Creek Flora.
Car11egie l11st. Washi11gfon, Publ. No. 346.
Et>;DO, S. (1933), Cenozoic Fossil Plants. Sup·
plements (in japanese). Jwanami's Ceo·
logical and Palaeontological Series.
(1938a). Cenozoic Plants from Tyosen(Korea). I and U (in Japanese). /oum.
Ceo/. Soc. laPa11. Vol. 45.
- - (1938b). On Fossil Plants from theEnvirons of Scndai. (in japanese). Ibid.
( 1939). Some New and Interesting Miocene
Plants from Tyosen (Korea). ]ub. Pub/.
Commem. Prof. H. YABE's 60th Birthday.
- - (1940), A Pleistocene Flora from Shiobara,

Kazuo HUZIOKA

122

Japan. Sci. Rcpt. Tohoku imp. Univ., Ser.
2, Vol. 2/, No. 1.
- - (1950). On the Fossil CarPitt:ts fromJapan and Korea. Short Papers JGPS,
No.2.
ETTISGSIIAU~ES, C. (1851), Fussile Flora vonWien.
- - (1866), Fossile Flora von Bilin I.
- - (1883), Zur Tertiarflora Japans. Stzzmgsb.
k. Akad. Wiss. Wien. Vol. 88.
GoPPERT, H. R. (1855). Die tertiare Flora vonShossnitz in Schlesien.
IIEER. 0. (1856), Flora tertiaria He!vetiae.
VoL 2.
- - (1878), Flora fossilis arctica. VoL 5, Pt. 3.
HU, H. H. and CHAI"EY. R. W. (1940). A
1\Hocene Flora from Shantung Province,
China. Car11egie lust. Wa.<hingtou, Pub/.
No. 507.
HUZJOKJI. K. (1938). Notes on Some Neogene
Plants from the Island of Heigun, Yama·
guti Pre!., with Descriptions cf 'the Genera
Carpinus and Sassafras. ]oum. Fac. Sci.,]Jokkaido Imp. U11iv .. Ser. 4, Vol. 4, Nos.
]-?

- - (19·l3a), Notes on Some Tertiary Plantsfrom Tyosen (Korea) L lbid., Vol. 7, No. 1.
- - (19431>), On Some Fossil Involucres ofOstrya and Carpinus from the l'viiocene
Deposits of Hokkaido and Tyosen. (inJapanese) ]ottm. Ceo/. Soc. ]apatl, Vol.
50, No. 602.
- - (1951). Notes on Some Tertiary Plantsfrom Tyosen (Korea) II. 1'ra11s. Proc.
Palaeo11t. Soc. ]apa,, N. Scr.. No. 2.
KAI"EIIARA, K. (1936). The Geology of theNorthern Part of Geizitu District, North
Keisyodo, Korea. (in Japanese) ]ourn.

Gtol. Soc. Japan, l'ol. -13, No. 509.
KoN'No, E. (1931), Cenozoic Flora from theCentral Shinano. in !IOLVIMA's Geology of
the Central Shinano. (in Japmese).
MAcGINITlg, II. D. (193.1), The Trout Cref'k
Flora of Southeastern Oregon. Camcgie
Ins/. Washington, Publ. No. 416.
MIKI, S. (19-11 ). On the change of flora in
Eastern Asia since Tertiary Period (I)The clay or lignite beds flora in Japan
with special reference to the.PimtS trifolia
beds in Central Hondo. ] apan. ] oum.

Botany, Vol. 11.
NATHORST. A. G. (1883), Contribution a Ia
flare fo sile du Japan. Kg/. Sv. Vet. Akad.
Hand/ .. Vol. 20, No. 2.
SAPORTA. G. DE (1867), Etudes sur Ia
vegHaux sudest France a l'epoque tertiaire.
IlL Amz. Sci. nat., 5 scr., Bot., Vol. 8.
TAt\Al, T. (1952). Notes a propos de quelques
plantes fossiles dans le groupe d'Ennichi(Ycngil) du Coree medionale. 1. Trans.
Proc. Palaeonl. ~oc. Japan, N. Ser .. No.8.
TATEIWA, L (1925),
Tyosen. No . .J.

Geological

Map

of

Localities of the described species
Ryuhokudo, Kokangen coal-mine, N. Kankyo
Do; Engelhardtia bed (l&iii~citt. 1i.SZIJ,t~!i\il, 'm~l:if<ij; Engellmrdtia .liif).
Salvinia pseudo/ormosa OISJII et HUZIOKA,
Cfr. Platanus Guillclnwe Goi'PERT, Fagt•slwraica liUZIOKA. F. pmtolongipetiolata
HUZIOKA. F. Uotanii lltJZIOKA. Zelkowa
Tibae OISHI et HUZIOJ<A, and Carpinus
Kodairae-bracteata I lUZIOI\A.
Kantindo. Meisen-gun. N. Kanltyo Do: Kan·tindo formation (.I&~;Jt.ii:i:. IUJIII:j]li~i'ftilttl;
rJZ ii\il•J 1Ft)
A cer sui>Pictmn SAt'ORT!I. A. czoam1111
OISHI et HUZIOJ<A, A. lri/obafum (STERN·
BERG) var. Productum AI.. BRAUN. A.
japolliCUIII THUNBERG, A. (samarae) spp.,
Fagus Protolongipetio/ata lltJZIOKA. UlmtiS
carPinoides GoPPERT, Zclkowa Ungeri(ETT.) KovATS. Carpinus carPitJOides
1\IAKINO, and C. erosa BLUME el/ipticibmcteala HUZIOKA.
Yutendo, Meisen-gun. N. Kankyo Do: Ryudo
formation (l&~:ft.i!i. 111)111:11~. 1lft!Jiifal; ltil;J

Iff).
Tilia distans NATIIORST, T. japonica
SIMO::O:KAI, T. meisemmsis HUZIOKA, T.
subnobi/is HuzloKA, Acer rotrmdatum
HUZIOKA, .4. subpiclum SAI'ORTA, A. sp..
A. (samarae) spp., Zelkowa Ungeri (ETT.)
KovATS, Betula myongchotwnsis. sp. nov.,and Ostrya shiragiana, sp. nov.
Kissyu.town, Kissyu-gun, N. I<ankyo Do:
White Shale of Kissyu formation (~ffl;Jt.
ii[, ~,'OIHlf\. ~tuH~: i'i+Hir!/1:1?.!,~\(.{}).

H uzxoKA: T ertiary Plants from T yosen (Korea)

PLATE 13

Notes on Some Tertiary Plants from Korea (Tyosen).

Ti/ia distans NATIIORST. Acer sttbpictum
SAPORTA, Ulmus shiragica llUZIOKA. and
Zelkowa Ungcri (ETT.) KovATS.
Kinkodo. Usen-men, Geizitu·gun. N. Keisyo
Do; Enniti series (fl:!ff.J.jt:iij, .i!J!ri'/l1i ..i?:;JII

lfif, -&J'tiM; i~HI~).
Tilia remo/iserrata OiSHI et lhJZIOI<A.
Acer rotrmda/um HUZIOKA, A. subPictum

III

123

SAPOWfA, A. /atsiaefo/ia IIUZIOKA. A.
ornatum CARR .. Ulmus shiragica HUZIOKA,
Ze/kowa Ungeri (ETT.) KovATS, Betulashiragica, sp. nov.. Carpimts carpinoides
l\IAKINO, C. miocordala llu et CHA:\'EY,
C. simp!icibmcteata HUZIOKA, and Ostrya
shiragimw, sp. nov.

Explanation of the Plate 13(The figures are of natural size)
The specimens are stored in the Institute of Geology and Mineralogy,
Faculty of Science. Hokkaido Univer~ity, Sapporo
Figs. 1-2. Betula myongchonensis. sp. nov. Loc. Yutendo. l'vleisen-gun, N. Kankyo Do, Ryudo
formation.
Figs. 3-4. Betula shiragica, sp. nov. Loc. Kinkodo, Usen-men, Geizitu-gun. N. Keisyo Do, Enniti
series.
Figs. 5-6. CarPinus miocordata Hu et CIIANEY Loc. Ditto.
Figs. 7-8. Ostrya shiragiana, sp. nov. Lac. Ditto.

124

PROCEEDINGS OF THE PALAEONTOLOGICAL SOCIETY
OF JAPANr B -+=ti ~I:J!~Il9':~m 56 ltilfii:)~_. JJH til 28 /,J'.
12 H 19 Fl A:IVir!J:.\i:).,:~~~H.Ii>F:f.i~JI!!~*X~f ~:.
*.' "L 1m fU!-t ( ~~~- 16 ~ ) o ~/liiJittt·lli t:. f;/~i'Dt

1m fl ~O>:!m GoJIJJ1tfl~ 1'1'YHi.H1Y~'I· V1EW11i!!.-T1l::-{ir n·--i.:J!i _g~%19f:~m 57 I:HH?Jl~J ~~:fll 29 ~r- 2
JJ 13 11-ll:~f;j;jifiJ-:¥: l]!~'fiiiJtl!t'i ~!IWEF::t&~t:.
Jk-cllHHH-r (~~-x·u ~)o F.#~i1il?f:;JEt:.~~M
Mill I;:j~O):ruJ La
I.

............................................ J!dfi ~ :"-:M
Trapa V1E!'ltfl:{'ll;:f,t.·-c ........ X:d'tL".SRJI
m~:iLffliO lfi~1l:1i......... ........ If: I& ;71~ {tSome Views on the lVIesozoic Verticil·
late Leaves from Jap:1n and Kon•a ...
.............................. KoBATAKE, Nobuo
Fossil Plants of the Kyongsang Formation........................ KnHATAKE, Nobuo
On the New Genus Taiwa11asagaoitrs
from the Neogene Formation of
Fukui Prefecture, the Inner side ofCentral Jap:m (ftil'in .................... .
........................... ... 1\IATS"t;O, Hidekuni
Occurrence of Miocene Foraminiferafrom Sasebo Group ( jt;;~) ..
.. .. .. . . .. ..... .. .... . .... . .. . .. MUHATA, Shigeo~lU!i\li~ ~!!jq.nll~.i:llii=J-v-H~---:: Jl. J • .;f.

(9}.1t!!h§) vifjif!!lu::: ·.:>~· -c ( ft~)............................................ Tt Jt- lU -i'il!f-iJll*'tP'iicfJ Bryozoa 1:::-:::>v·-c (-l"il~)( ftitl~) ... .. ... .. .. ... .. .. .. . .. ... A,- Ji~ fJ l~
A New Species of Edentula from theUpper Triassic Mine Group of
Yamaguchi Prefecture, Japan .........
................................. NAKAZAWA, l<eijiDiscovery of AclinodontoPhora andother Pelecypods from the Permianof the Kitakami Mountainland ( f~mn........................ IcHIKAWA, Koichiro
Turcicu/a v~{(:::Ufflit:::-::>v· ·c (f~~).. .
..................................... *Illtl:!!ifiH!U.\IJJ~ttrt 10 1l: 1i ... . . .. .. . .. .ill! ill ti~ ~lc
On the Occurrence of GlyPtoPhiceras
from the Province of Yamasaki,
Hyogo Prefecture, Japan ...
NAKAZAWA, l<eiji & SIIIMIZU, Daildchiro

2.

itlii~!Htifitfllll;or... ~l~Jimmt

Oinomikadoitw ogiensis :1\IATSUN;\GA 1:::-:::>.... -c ( fl;;~/0 .. . . .. ..... ~ 7k ::¥:
:lf;J:tiJiJ:i!;No (}Wflf-l:lifiJN]t.:: '?II•"C ...
. .. . .. . . . . ... .. ... .. . ... . .. . . . .... .. .. . ~ III lUi :.;;

a. :!l:J:Illit!!.:::~~llliill~!f!tfl< ... { : ;lf1 i£ ~~4. :f[;if;i:li:Jr:lu 1\fericenaria Jii! Vfl:Tit:::-:::>.... -c.. ............................... ffi. it

tlf

5.

Nl'ptmzea shitakaraensis V'11:~ ......

6.

Yoldia laudal,i/is YoKOYAMA t:::-::>

7.

~'F[lf,JilJ:ft::iii'tilf-iJII~PfH!'Fs.

'l•m!lt#JWJcrJ1'f.1l::nttr-m (ftil'J\!) ..... .

9.

An Occurrence of Koni11ckioceras
from the Japanese Permian ........
......................... HAYAS:\KA, lchiro
Notes on the Motodo Volcanic
Conglomerate, IIida i\Iountainland,with Special Reference to Some
Microfossils of Its Limestone
Pebbles ( ft~) ......... KmmHJ, Kenji..................................... ;f~ Jt·v•"C (f\';;~n

10.

*

ill

u

.................
~i- :lit·• J:$" itft
Vfl:::(j (i~~) ................ 7!<
fi

Jf.

. .................................... *· m :m tr

r 11 '1.:ti ~tim~~ 1954 ~Hit !.J'-~J ag;Fn 29'.f. 4 n 30 IJ f.~l117..:~iJ11JlJ9':}\ill:.:JR-rOOIIH-t o
JiiJ~IfCJ:L:· ;ff~~O)_I:. ~Jl.IHB 13 ~.t.e~ OJ:!m<i&iE Gt:o
( / ;,-!;1·-7 1 ;,-(;J:~:Y!fllo1JiJf)~1;

13 ~-~·{~l;tJE~ft&f 6001Il (filL:{£~~~fl&jO 3$):rt: I}) 195-1 &f-Jlf (1 _g -12 JJ) »· &-*~JllJt::: J:::5 ® ~HN4ltl\t:::r.t Special p1pers ).kV:--{'
v ill illH a: 1!; tr oTrans. Proc. P::~laeont. Soc. Japan, N.S .. No. 13, pp. 125-130, Pl. 14, June 15, 19j4

244.

ELECTRON-MICROSCOPIC FINE STRUCTURE
OF FOSSIL DIATOMS. I*
HARUO OKUNO
Kyoto University of Textile Fibers

1tfi1.1t~<Ol1Ffiiiltl!lll~ii'Uill~~.

-ttftfi,

I: {t::fift,~<O'iliri!i~iU~I>Uill~/4iiH: iUf~r o : l: ~:, M:

mm!. 'li:lfl!l!.&V:.Illt'tt~4lJ/. Mfil:$:1J:ct~~tt..<:t?:\ltH;.t.-:., 'liH!i~.mt~J: Ht1i~~"J#(mrJ;r.:-=>v·<: txt..t~o Coscinodiscus elegans (W.i!tr.f:;JRfRIIIfl:tV:~.U:-" .(~rllillf.lllfpf.).
Cosc. linea/us ( W.ilft 7 .C.iR !Ritfilli). Cosc. m.ugin!Jtus (P.i!tt J .\1; ~i !WIIIIf.tf ), Cosc. ocufusi,.idis (::kfi'.iif.flli JTit:l'J.H.I' filll!h\:fi.,}tfil€) t~: c tt:? ~. k.fl...f.tt.u.>'*~ro~~t.9iJH:~ t... <St\ Lt~o!t!'I'Hf:iif

pore. (Cf. 0KUNo, 1949, Bot. Mag. Tollyo,
vol. 62, p. 136, fig. 1; 1951, ]ourn. ]ap.
Rot., vol. 26, p. 308, fig. 1; 19S2, I.e.,
vol. 27, p. 48, 350, fig. 1.) In the sieve
membrane of the hole, I can not yet
ascertain the existence of such distinct
sieve pores as in the loculus. Ami in
the fossil frust.ules, the sieve membranesof the hole and the loculus are often
lost by weathering.
According to my researches, the electron-microscopic fine structure of thefrustule pores are peculiar to the spe.
cies. And, in general, in the cells of
the same sp:!cies, variety or form, thefrustule pore of the same fine structure
was found. Thus. I have probationallyclassified the diatom frustules by theirelectron-microscopic fine structure of
the frustule pores into about 23 groups(0KU:-<o, 1953, Bot. 1\{ag. Tokyo, vol. 66,
pp. 121-124). Sometimes, as noteworthy
facts, even in the frustule pores of the
diatoms of different genera, families, ororders, I could find common electronmicroscopic fine structure. For example,
the frustule pores of Araclmoidiscus
ornatus ( Centrales - Actinodiscaceae;
0KUNo, 1949, Bot. Mag. Tokyo, vol. 62,

Introduction
Some of the fine structure of the
diatom frustulcs are far beyond thehighest resolving power of the lightmicroscope. Especially the fine structureof the frustule pores arc so minute thatthey can be revealed in detail only by
the electron microscope.
The frustulc pores can be classified
by their electron-microscopic fine structure into two types. one the ' hole*'*·.
and the other the ' loculus' (Text-fig. 1).
The former is a pore, not locular andopened freely or closed with one sheetof sieve membr,lne, and the latter is alocular pore closed with two sheets ofmembranes, the outer sieve membrane
and the inner cover membrane. The
sieve membrane of the loculus is usually
perforated by many sieve pores of various shapes and siz~s. and the cover
membrane is perforated by a cover"' 1) Read Oct. 10, 1953 : received Oct. 14, 1953.

2) This resear~h was aided by a Grant in
Aid for Scientific Research from the Ministryof Education.
"'* In my previous papers, written as · simple
pore'.
125

Haruo OKUKO

126

0

'{

0

h

0

II<

A

~:.rl•____• I. • ---Jt-·_ j)l,.
~
f-CP

I(f 0
II<_;

A

II)
l

_......_~ _B~-

Text-fig. 1. Diagram of the frustule pores. A. A1, Hole.
E. Loculus (Coscinodiscus oculus-iridis). I. View from obliquely
above, with the idealistic longitudinal (pcrvalver) section.
II. Idealistic longitudinal (pervaiV('r) section. c, Cover mem·brane. cp, Cover pore. f, Frustule. h. Hole (in fig. A, with,and in fig. A 1, without the sieve membrane). 1, Loculus.
p, Sieve pore. r. Ray. s, Sieve membrane. sm. Side membrane. ss, Secondary sieve membrane.

p. 97, pl. 3, fig. 3), Cocconeis scutellum(upper valve) (Pemzales-Aclmanthaceae; OKuNo, 1950, I.e., vol. 63, p. 101,
pl. 3, figs. 6-6'1 ), and Didymos/Jftenia
geminata var. cm·vata (Pemtales-Navictt/aceae; 0KUNo, present study, II, pl. 2,
figs. 5a-d), <ill these have the similar
sieve membrane with the distinct, dendrifonn thickenings. The frustule poresof Triceratittm Slzadboltiamem var. e!ongala ( Centrales-Biddulphiaceae; 0KcNo,
1950, Bot. Mag. To!?yo, vol. 63, p. 99, pi,
2, figs. 4, 41 ) and Biddulphia Titiana(Cetztra/es - Biddulphiaceae; 0Ku:--:o,Electron micrograph, no. S. 338-340-not
yet published) are similar, both having
2-3 horse-shoe shaped sieve pores disposed oppositely or circularly. On theother hand. in some species of the same
genus, I could find the frustule pores of
distinctly different structure. For example, Aclma1ztltes · /ongipes has thenetveined sieve membrane (OKUNO, 1953,

I.e., vol. 66, p. 6, pl. 2, figs. 1-lb "),while Aclz. lanceo!ata (KoLBE, 194.1, Ber.
nt. Bot. Grs., vol. 61, p. 95, pl. 4, fig. 15;
0J<UNo, 1953, I.e., vol. 66, p. 7, pl. 2,
figs. 2, 21) and f. ventricosa (OKuNn,
present study,
II.-in print) havethe sieve membrane with round sieve
pores arranged in transvers~ rows.
Navicula cuspidata var. ambigua ( OKUNn,
1953, I.e., p. 5, pl. 1, figs. 2, 2') andNav. lyra var. constricta (OKuNo, 1950,
1. c., vol. 63. p. 103, pl. 4, figs. 2, 2')have, like many other Navicula species,
transverse rows of roundish-rectangularholes, while Nav. yarrettsis (OKuNo,
UJ50, 1. c., figs. 1, 1') and Nav. elegmts(OKUKo, 1!J50, 1. c., figs. 4, 4') have thetransversely broad loculus with finely
porous sieve membranes, which arc
rather peculiar to Pimmlaria! Thus,
the fine structure of the frustule poreis on the one hand peculiar to thespecies and on the other hand somewhatElectron-Microscopic Fine Structure of Fossil Diatoms.

relationless to the present light microscopic classification of diatoms. And, it
may be possible to suggest a new classification of diatoms by their electronmicroscopic structure, instead of thepresent light-microscopic classification.
It is conceivable that the frustules ofthe fossil diatoms, especially their delicate sieve membranes, are more or lessdamaged by long physical and chemical
weathering. The degree of destructionof the frustu!es will be determined by
the total of the physical and chemical
weathering. And the longer and more
powerful the geological weathering, themore complete the destruction of thefossil frustu!es will be. Thus, the degree ofdestruction of the frustules ofthe same species from different localities
will indicate the different intensities ofweathering. Further, it may even be
possible to trace the development of
the fine structure of the diatoms or thedevelopment of the diatoms themselves
by comparing in detail the fme struc·ture of the fossil frustules of different
geological ages.
Diatomaceous earths, both of fresh
water and marine origin, cover a wide
range of applications in major industrial
fields. After refined, they are used as
the filter-aid in conjunction with filter
presses or other equipment in the filtration of liquids of all kinds-acids, beer,casein, cider, enamels, fruit juices, gelatine, glucose, gums, milk, oils, penicillin
and other pharmaceuticals, soap, sugars,
water, wine, etc. As. fillers, they areused in the following products-asphalt,
carriers of catalysts, ceramics, concrete,polishes, rubber, textiles, etc. As thermal insulators, the pulverized diatomaceous earth and the calcined diatomaceous bricks are employed to reduceheat waste, to save fuel and increase
efficiency in the following equipments-

I

121

boilers, furnaces, kettles, kilns, ovens,.
tanks, tubes, etc. These vast uses of the
diatomaceous earths almost entirely
depend upon their specific physical andchemical properties-lightness, purity,
inertness, heat resistance, uniformity andextraordinarily high porosity of thefossil frustules ! As the excellent filtration and absorption power of the diatomaceous earth depends, to a certain
extent, upon their minute frustule pores,
the electron-microscopic studies of thefine structure of the frustule pores will
foreshadow improvements of the indus·
trial application of diatomaceous earth.
· The electron micrographs presented
here were photographed partly with the
SHIMAnzu magnetic 'SM-II' electron
microscope at our laboratory, partlywith the 'SM-CII' at SHIMAnzu Works,
Kyoto, and partly with the 'SM-I' at
Osaka University, each operation atabout 40-50k V.
I wish to express my hearty thanks.
to Dr. Shin-ichi SHIMADZU and his collaborators, Messrs. Yoshinori Tor-;oMURA
and Ytitarb W ATANAllE of Shimadzu
Works, and Dr. Gompachiro YASUZUMI
and his collaborator, Mr. Akira T A:-<AI\Aof Osaka University, all of whom kindly
gave me the opportunitY of taking many'electron micrographs at their laboratories. Further, I take this opportunitYof thanking Mr. Kiichiro KuRosAWA of
our laboratory for his aid in many
ways.
Preparation of Fossil Diatoms
for Electron Microscopy
The fossil diatoms being almost naturally removed of their cell contents bylong weathering, they are luckily inmany cases ready for the electron·
microscopic preparation. In the present
research, in order to obtain the electron

Haruo OKUNO

128

micrograph of the- undamaged frustules,
treatments as boiling the fossils inacid or calcinating, them at high temperature were avoided in the course of
preparation. After being washed in·distilled water, the fossil frustules were
dropped on the slide glass and wereprepared as the dry preparation. While
examining . the dry preparation under
the low-power light microscope, a piece·Of the upper or the lower valve, or its
fragment, was caught with the help of
a sharp needle operated by the free!land, and was transfered and attachedto the collodion membrane of the sample
holder. The supporting collodion membrane with the fossil frustules on it, wasexposed for two or three seconds toaq\}eous vapour to fix the fossil frustules.
Sometimes the frustules were attachedto the sample holder without the supporting membrane in such a mannerthat a portion of the fossil frustule wasprojected into the pore of the holder to!Je exposed directly to the electron
beam. Such a preparation, without the
supporting membrane, I called the'direct preparation' (0KuNo, 1953, Bot.
Mag. Tokyo, vol. 66, p. 159). The direct
preparation, after being exposed toaqueous vapour as the collodion preparation, was put into the electron
microscope for observation. From thedirect preparation, without the hindrance<>f the supporting membrane, I could
always obtain more exact and sharper
images of the fine structure of the fossil
frustules than. from the collodion preparation.

~ch1886, At. Diat., pl. 58, fig. 7-MILLS, 1933,

Index, p. 470.-0KUNO, 1950, Bot. Meg.
Tokyo, vo/. 63, p. 98, pl. 1. figs. 4, 4'.

Valves about 38-70 p. in diameter.
Central area hyaline. Frustule pores
polygonal, locular, about 4 in 10 p.,
arranged in radiating rows. In thesubmarginal zone, with 2-3 circles ofsmaller frustule pores. Marginal zone
striated, striae about 13-14 in 10 p.. Inmany specimens from ·Hirosaki Basinand Oki Island, the sieve me~b.ra~~s ofthe frustule pores were almost completely lost as shown in fig. lb. Only
in few specimens from Oki Island, I
could find ;nore or less well preserved
thin mern:braries, which I thought to be
the sieve menibranes (fig. lc). These
membranes in the. loculi were very thin,and electron-microscopically seem notporous.
According to my research,
Coscittodiscus species both of Jiving andfossil forms, were found with distinctly
porous sieve membranes. And such asieve membrane without sieve pores asin the present species, is not yet foundby me in other Coscinodiscus species.
Habitat : Maririe, planktonic.
Occurrence: Fig. la. In diatomite.
(Specimen, no. 1346) Sawane-cho, Sado
Island, Niigata Prefecture.
Upper
Miocene, Nakayamatoge
Formation.
Fig. lb (Obtained from the specimen
boiled in hydrochloric acid). In mudstone. (Specimen, no. m 744, collectedby T. KANAYA.) Fig'. lc. In diatomite.
(Specimen, no. 923) Mt. linoyama.
Saigo-cho, Oki Island, Shimane Prefecture. Middle or Upper Miocene or
Lower Pliocene, DOgo Group.

Description of Species. Coscinodiscus elegans GREV ILLE

Coscinodisczts lineatus EHRENBERG

Pl. 14, figs. la-c.

Pl. 14. figs. 2a-c.

Coscinodiscus e/egans GREVILLE, A. ScHMIDT;

CoscinodiscztS /ineatus EHRE:\"BERG, HUSTF.DT,

I

Electron;Micr?scopic Fine Structure of Fossil Diatoms.
1930, Kieselalg., Teil. 1, p. 392, fig. 204.Mir.r.s, 1933, Index. p. 483.-Lo!>G, FUGE
and SMITH, 1946, J ourn. Paleont. vol.
20, p. 103, pl. 16. fig. 5.-0KUNO, 1949,
Bot. Mag. Tokyo, vol. 62. 'p, 97, pl. 3, fig.
2 ; 1950, I.e .. · p. 98, pl. 1, ·figs. 5, 51 ;1952, A.t Fos~. Diat., pl. 8. fig. 1, pl. 19,
fig. 1.

Valves about 50-130 (30-150) p. in<liameter. Frustule pores locular, usually hexagonal, about. 4 (3-5) in 10 p.,
arranged in three straight liQes decussating at ·about 60 'degrees. Margin11l
zone striated, striae about 8-9 (7-12) in
10 p.. Sieve membranes of the loculi
with round sieve pores about 150-200m p.
in diameter. Sieve pores about 3.5-5 in
1 p., arranged in three straight or slightly
curved lines decussating at about 60
degrees. Cover pores of the loculi,
round, about 1.2-1.6 p. in diameter. In
fossils, the sieve membranes are usuallymore or less lost.
Habitat: Marine, pelagic.
Occurrence: Figs. 2a, b. In diatomite.
(Specimen, no. 1346) Sawane-cho, Sado
Island, Niigata Prefecture. Upper 1\Ho.cene, Nakayamatc)ge Formation. Fig.
2c. Living form; ·Antarctic plankton.
{Specimen, no. m620; .sent from theTaiyo Fishery Company, 'Tokyo.) 171°411
W: 77°7 1S. Jan. 1951.

Coscinodiscus marginatus EHRENBERG
Pl. 14, figs. 3a-c.

Coscinodiscus marginatus EHREKBERG, HlisTEDT, 1930, Kieselalg., Teil. 1, p. 416, fig.
223.-MII.LS. 1933, Index, p. 484.-Lo:-;G,
FUGE and SMITH. 1946, Journ. Paleont.
vol. 20, p. 104, pl. 16, fig. 13.

Valves almost flat, sharply fall off at
the margin. Diameter about 55-80 (37200)p.. Fru,stule pores polygonal, locular, 1.5-2.5 (1.5-4) in 10 p.. MarginalI

129

zone broad, with coarse striae about 4'-5(1.5-6) in 10 p.. Sieve membranes of theloculi with round to roundish-polygonal
sieve pores, about 3 in 1p., about 500mp.
in diameter. In many frustules, thesieve membranes are lost. In the frus·
tules of the living forms, I have foundthe secondary sieve membrane which
divide the sieve pore into several secondary sieve pores (fig. 3c). In the fossils,
I could not yet find such secondary
sieve membranes. They are probably
lost.
Habitat: Marine, pelagic.
Occurrence: Fig. 3a, b. In diatomite.
(Specimen, no. 923) Mt. Iinoyama, Saigocho, Oki Island, Shimane Prefecture.
Middle or Upper Miocene or Lower
Pliocene, D6go Group. Fig. 3c. Living
form; North Pacific plankton. (Specimen, no. m698; collected by H. MAEDA.)
16:1°61 E: 49°30'N. Jul. 1952.

Coscinodiscus oculus-iridis EHRENBERG
Text-fig. 1. B: Pl. 14, figs. 4a-c.

Coscinodiscus ocu/us·iridis EHRENBERG, MILLS,
1933, Inrlex. p. 491-0KUNO. 1950, Bot.
Mag. Tokyo, vo/. 63, p. ·232: i951. Geo/.
Sci. Kyoto, no. 6, p. 61. pl. 3. figs. 4. 4'-

Valves about 160 (lC(}-300) p. in diameter. Central rosette distinct, some·times with a small hyaline area in its
centre. Frustule pores locular, 3-4 in
10 p., largest at about the half of theradius of the valve, and increasing to
4.5 at the margin. In both specimensfrom Ishizaki-mura and Yamada-mura,the sieve membranes of the loculi are
well preserved. Sieve pores round to
roundish-polygonal, about 100-200mp.
(Yamada specimen)
to 150-300 mp.
(Ishizaki specimen) in diameter, somewhat concentrically distributed over thesieve membrane (Text fig. 1, B-p). In

130

Haruo0KUNO·PI. 14, · fig. 4c, the sieve pores at themarginal part of the sieve membrane
are seen faintly through the cover
membrane. Secondary sieve ·membranes(cf. OK uNo, 1951, ]ourn. ] ap. Bot., vol.
26, p. 308, Text fig. 1) are almost completely lost. Cover membranes distinct,
somewhat thick at their inner margins.
Cover pores round, about 1-1.5 f.£ indiameter. On the cover membrane,
several rays radiating from the borderof the cover pore to the corners of theloculus are seen with the light microscope (Text fig. 1, B--r).
Habitat: Marine, pelagic.
Occurrence: Figs. 4a, b. In clay.
(Specimen, no. lcHJHARA, K 10) Yamadamura, Mishima-gun, Osaka Prefecture.
Pleistocene, Ibaragi Formation, Osaka
Group. Fig. 4c. In diatomite. (Speci'men, no. 1327, E153) lshizaki-mura,
Kashima-gun,Ishikawa
Prefecture.
Miocene, Wakura Formation, Fugeshi
Group.

E.xplanation of Plate 14
L. l\'1.: Light 1\licrograph. E. M.: Electron 1\licrograph.
Electron micrographs without special remarks were all obtained
from the direct preparations.
Figs. la-c. Coscitwdiscus elegatJS GREVILLE. la. Sawane-cho, Sado Island. Niigata Pre!. (L. M.
x300). lb. Hirosaki Basin. Aomori Pref. (E.:M.x2200). lc. Saigo·chO, Oki Island, Shimane
Pref. (E.M. x 9600).
·Figs. 2a-·c. Cosci11odiscus linea/us EHRENBERG. 2a, b, Sawane-cho, Sado Island, Niigata Pre!. 2a(L.M. x 600). 2b (E.M, x 7500). 2c, Recent; Antarctic. (E.M. x 12500).
Figs. 3a-c. Coscinodiscus marginatus EHRENBERG. 3a, b .. Saigo-cho, Oki Island; Shimane Pref.
3a (L.M. x 800). 3b (E.M. x 4500). 3c, Recent; North Pacific. (E.M. x 11000 ).
Figs. 4a-c. Cosci11odiscu.~ oculus·iridis EHRENBERG. 4a. b. Yarriada-mura, Osaka Pre!. 4a (L.M.
x 500). 'lh (E.M. x 13000). 4c, lshizaki-mura, Ishikawa Pre!. (E.M. x 7000).

OKu No: Fine Structure of Fossil Diatoms

3a

4a

PLATE

2b

2c

4b

4c

3b

14

Trans. Proc. Palaeont. Soc. Japan. N.S., No. 13, pp. 131-132, Pl. 15, June 15. 1954

245. RECENT AND FOSSIL SPECIES OF BRISSUS FROMRYUKYU*AKIRA MORISHITA
Geological and Mineralogical Institute, University of Kyoto~~-~ Brissus ~ffl.1:.f!J<r J: tf{t:Ufl: :1r.*!ll~~fk!i!f#Til~lfigff~:4: Jtl K1im.I'Hii Brissus
VJ-!Jlli:.f!li.<a J: V.:ft.t'l ffli kJ!/fj t.., jiilj~ a:J:I:.~cii3l'H.• {l:.:?if1i"C:I:f!~J1E{i?~. nn~{i?~~f~ff ~tt-l;:(y·~.!:a:-tl'iMiL.t::o

~r

dl.

I wish to acknowledge my indebtedness to Professor Yoshikuni HIRAIWA.
and Assistant Professor Sadahiro MIYAimof the Zoological Institute, Kyusyu University for their kind advices. and toProfessor Jiro MAKIYAMA of the Geological and Mineralogical Institute, Kyoto
University for revision of this description.

When I called on the Zoological Institute of Kyusyu University in April ofthe year 1952, I found the recent andfossil species of Brissus from Ishigakijima, Ryukyu Islands in the late Hayato
IKEDA's collections of Echinoids. Professor Yoshikuni HIRAIWA kindly permitted me to examine both the specimens,
consequently identified with Brissus
latecarinatzes LESI\E.
Fortunately as
they were obtained at the same place,Ishigaki·jima, it seems interesting tocompare them in detail, observing specially the preservation of the fossil
specimen. The fossil one is found in thelimestone (Ryukyu Limestone) which
is Pleistocene in geological age.
It is not deformed, but the odd anterior ambulacrum, the genital pores, theperipetalous fasciole, the subanal fasciole
and the tubercles are obscure. It isbelieved that many fossil echinoids do
not preserve their fascioles.
Fossils of this species has been known
to occur in Farsan Island of Red Sea(Pliocene), Java (Upper Miocene), Daitojima (Pleistocene).
This species is known Jiving in Red
Sea, Indian Ocean and Pacific Ocean.
Most probably this species lives in thedepth of 1 m. under the tidal planes.

Description of Species

Family Spataugidae GRAY
Genus Brissus LEsKE

Brissus latecarinaltts LESKE
Plate 15, Figs. 1-6.
1855 Brissus agassizii, L. DtiDERLEI:-<, Arch. f.
Naturg. !ahrg. 51. Hell 1. p. 108.
1900 Brissus agassizii. S. ToKUNAGA, Zoo!.
Mag .. vol. 12, p. 399, pl. 18. figs. 1-6.
1917 Brissus lalecarinatus, H. L. CLARK. Jlawai·
ian Ech., p. 219.
1931 Brissus agassizii. H. OHSHJ:MA, Zoo/.
Mag., vo/. 43. tw. 516, p. 601.
1933 Brissus latecarinatus. S. N!SIYAl\IA, Echinodermata. p. 53.
1942 Brissus latecarinatus. S. NISIYAMA, Jour.
Ocea11. Soc. ] apan. 1. p. 24, fig. 12.
1948 Brissus sp. indet. "'· I. HAYASAKA, Acta

Ceo/. Taiwanica. vol. 2. no. 2, p. 110, pl.

* Read Nov. 20, 1952; received Feb. 9, 1953

2, fig. 2.
131

132

Akira 'MORISHITA

Description :-The test is elongatedoval, rounded at the anterior ambitus
and pointed in the posterior margin.
The greatest height and width are on
the line between the marginal extremities of the posterior paired ambulacra.
The interambulacrum V is elevatedmaking a keel-like ridge. The abactinal<;;ide is generally elevated from theambitus to the centre, but the actinalside flat.
The anterior sulcus iswanting.
The apical system situates at anterior
1/3 of the longitudinal diameter. The
genital pons are 4 and the posterior
paired pores are larger than the anterior paired ones.
The anterior paired ambulacra forming an angle of about 160° one another,are shorter than the posterior ones (3/4),
and almost straight but slightly concave
anteriorly. The posterior paired ambulacra, forming an angle of about 25°, areconcave outwards at the extremities.
The odd anterior one is narrow, straight,
and degenerate. The peripetalous fasciole is distinct, entering in each interambulacra (indistinct in fossil species.).
The subanal fasciole is distinct too,situating under the periproct, concave
at the middle of upper side and straightin under side (indistinct in fossil
species.).
The peristome at anterior 1/6 of theactinal longitudinal diameter, forming acrescent shape.
The periproct is at the posterior
margin of test, and oval-shaped.
The tubercles are irregular and smaller on the actina! side than on theabactinal (indistinct in fossil species).

Height.
Ant. Paired Amb.;
Length.
Width.
Post. Paired Amb. :Length.
Width.

51mm.

58mm.

29mm.
5.4mm.

29mm.
5.2 mm.

37mm.
4.2mm.

35mm.
5.0mm.

Related Forms:- The relation with aJapanese species, Brissus agassizii DoDERLEIN is not known. But according to
DonERLEIN's original description boththe species seem to b~ just alike. Brisszes sp. (\: from Ryukyu Limestone of
Taiwan by I. HAYASAKA is very muchallied to the present specks except for
it's smaiier size. Brissus sp. /3 of HAYASAKA from Kiko Formation (Upp:-r
Miocene) of Taiwan differs from thisspecies in its smaller and wider anteriorsulcus, the odd anterior ambulacrum
being in shallow and in its wide depression, and smaller size.
Geological Horizon :-Ryukyu Limestone (Pleistocene), Recent.
Locality :-Ishigaki-jima, Ryukyu Islands.
References
CLARK. H. L. (1917). Hawaiian and other
Pacific Echini, Spatangidac. Mem. l'ifus.
Comp. Zoo! .. -19.

DoDERLEIN, L. (1!185), Seeigel von Japan und
den Liu-Kiu Inseln, Arcltiv f. Naturg..
]alzrg. 51. Heft 1.

HAYASAKA, I. (1948), Notes on Some Fossil
EchincJds of Taiwan-IV. Acta Geologica
Taiwa11ica, t10l. 2, no. 2.
NISIYAMA, S. (1933), Echinodermata, lWA·
NAMI·Koza (Manual of Geology andPalaeontology).
--, (1942), Recent Shallow Water Echinoids
from the Micronesia, Jour. Ocea11og. Soc.
JaPan, 1.

Measurements:Recent
FossilSpeciesSpeciesLongitudinal Diameter 100mm. 109mm.
Transverse Diameter 83 mm.
88mm.

OHSHIMl\, H. (1931). Brissus ogassizii in" Miscellaneous notes on the Fauna of
Amakusa 5" Zoo/. Mag., L•ol. 43, no. 516.
TOKUNAGA, S. (1900). Japanese Echinoids,
Zoo/. Mag., vol. 12.

MoRISHITA: Brissus from Ryukyu

Explanation of Plate 15
Brissus latecarinatus L ESKE
Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.

Recent Species. Abactinal Side. x 2/5
Recent Species. Actina! Side. x 2/5
Recent Species. Lateral Side. x 2/5
Recent Species. Posterior Side. x 2/5
Fossil Species. Abactinal Side. x 2/5
Fossil Species. Actina! Side. x 2/5

P r.ATE 15

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Announcement
Change in By-laws
On the occasion of the Annual Meeting of the Palaeontological Society ofJapan, held on April 30, 1954, it was decided upon to revise Article 13 as Indicated(in italic) below.
Article 13. Rates for annual dues shall be 600 Yen (Domestic) for regularmembers and 3 dollars for foreign members.
Addendum
According to the By-laws of the Society, for the fiscal year of 1954 (January
to December), foreign members shall receive, besides the Journal, special papers
as Issued (postage included).

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