a -lt" 1:t ± ij) ~ ~{U..~· ic.lJ

Transactions and Proceedingsof thePalaeontological Society of Japan
New Eeries

No. 35

Palaeontological Society of japan
September 15, 1959

CONTENTS
TRANSACTIONS
Page365. Some Pelecypods from the Upper Jurassic Sakamoto Formation in Central
Kyushu, Japan ......................................... Minoru TA~!URA

113

366. On the Miocene Pectinidae from the Environs of Sendai; Part 15, Pecten

cosibensis YoKOYA~tA and its related Species ......... Koichiro i\l-\suoA 121
367. Some Pelecypods from the Tsukinoura Formation in :\Iiyagi Prefecture .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Itaru HAY AMI

133

368. Some Pelecypods from the upper Aratozaki Formation including a new
Genus Kobayashites . ...................................... ltaru IIAYAMJ
369. Spinomarginifera found in Japanese Permian.

. ........... Koji NAKAMURA

138
143

370. "Hakevplfia" and "Edentula" from the Late Triassic Mine Series inWest Japan ........................................... Akira ToJ<UYAMA 147
SHORT NOTES
5.

Identity of Algal Genus Tubiphytes 1\l.o\sLov, 1956, and Hydrozoan Genus

Nigriporel!a R1cnv, 1958 .................................. Kenji KoNJSJII 142
PROCEEDINCS.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

156

President: Tciichi KoBAYAsHI
Councillors: Kiyoshi AsANo, Riuji ENoo (Publication), Seido ENno, Haruyoshi FunMoTa (Treasurer), Shoshiro HAXZAWA, Kotara HATAr, Ichiro liAYASAKA, Kazuo
HuzJoKA, Nobuo lKEBE, Jiro i\Lo\.KIYAMA, Tatsuro i\IATsu~toTO, Masao 1\ltNATo,
Tokio SHrKAMA (General Affairs), Fuyuji TAKAI (Editor), Ryuzo ToRIYAMA
Secretary: Tetsuro HAN AI
Assistant Secretary: Takco IcHtKAw A

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

Trans. Proc. Paleont. Soc. japan. !\. S., No. 35. pp. 113-120, pl. 12. Sept. 15. 1959:~G5.

SO:IVIE PELECYPODS FROl\I THE UPPER JURASSIC SAKA:\WTO
FOR~IATIOKIN CENTRAL KYUSHU. JAPA?\'*i\11:\0RI.i TAl\fLRA

Faculty of Education, Kumamoto University:!J'i.;j;:m'Ji!€0::-flc~fUi:..t:Hil :.:.=1. 7lfi:i&*mi~0=-.ra~1t.Eo:>? ;. *;£li1Xo:> Hetero·donta &tY :1\Iyacid '(1f,c::~-t;,; t 0 "£ 13 fill (? ; 8 tfrfi!l) ~ell& v t:,l'viyacid (i: ~-,;- 7.>

t o:>:t-~\tr::fJ!H.r:;r:ftL'IRlltf7:JtmU.:: &O)n:g;t,. tU:o:>;Jc~f;f!:;t)'J.~r::i!i(l::.tflli1i''" <. 3?.:;t;::lll(J):/::J.7lfd)·t:> t. 111lml0f.~0!r~®!lftpt;,<7) 2 rn.:r~t·-cc:i:*c<C~0t0-c0-.;,
fB

i::t

~

This is the third report of studies on
the pelecypods of the Sakamoto formation. The following 13 species of pele·
cypods including 8 new ones are de·scribed on this occasion:

Tol\yo for his untiring guidance and tol'vir. I. l-LnAMt of the Univ. for his as·
sistances in laboratory works.

Opis ( Trigonopis) torinosuensis Kr~tL'RA
Opis (Trigonopis) trigona/is T A~ll'RA. newspecies
Opis (Coelopis) tanonrensis T:\~rCRA. newspecies
Corbula g/obosa TA~IURA. new species
Lucina tsunoensis Kt~IVtL\
Eomiodon kumamotoensis TAMt;RA, new

Family Astartidae
Genus Opis DEFRA:'>ICE, 18~5
Subgenus Trigonopis ~k;.;tER·CIIAUlAS.

1887

Opis ( Trigonopis) foriuosuensis KrMURA

species

Plate 12. Figures. 11-13.

"Eocallisla" regularis TAMURA. newspecies
Anisocc.r:lia sp.
Tancredia rnstrata TAML'RA. t:ew species
Pleuromya ? punctostriae TA~Il:RA, newspecies
Pholadomya ~ ashikiteusis TAMURA, new1956.

Opis ( Trigmzopis) torinosuensis. Kr~IURA,
p. s;-. pl. 1. fig. 10.

Several well preserved specimens,
though partly deformed, are allied tothis species. The Sakamoto form islonger relative to height and is larger
and \Vider than the Torinosu form.
Umbo!1a1 inflation is distinct in the Sa·
kamoto form.
1Heasurements :-species

Arcomw1 .' sp.
Goniomya sp.

For stratigraphical notes the reader
is referred to the first report (1959-1).
The writer wishes his hearty thanks
to Prof. T. KonAYAsur of the Univ. of

R. (l\>Evi. 3087)
R. (:'lEvi. 3088)
L. (MiVL 3089)
R. (:VL\1. 3090)* Received Sept. 24. 1958 : read Dec. 7.
1958.

ll;j

L
15.0mm
20.0
20. u
11. 5

H

Th

20. Omm
17. 0

8. Omm
8. 0
8. 0

19 0
11. 0

4. 5

114

A1i1wru TAMURA

Occurrence:- Locs. !, 4. 6, 8.

Occurrence:- Locs. 1, :1, 6.

Opis (Trigonopis) trigona/is TA:-rl:RA,

new species

Opis (Coe/opis) tanourensis T A!\IUR:\,
new species

Phtte 12. Figures 14-16.

Plate 12. Figures 5-7.

Description :-Shell small in size, probably suhequivalve, very inequilateral,prominently convex. much longer thanhigh; postero·ventral margin obliquelyelongated; umbo at about 1/4 fromanterior end, prosogyrate and a iittle
incurved: posterior and ventral margins
long and nearly straight or slightlv
rounded; anterior margin short andarcuate: lunule short but distinct:
surface ornamented \Vith fine andnumerous concentric striae; cardinal
tooth strong and fang-like in rightvalve: probably two cardinals in left
valve: 1lat belt along ventral margin
narrow; internal margin denticulate;adductor impressions clearly impressedon flat belt of margin; posterior one
twice as large as anterior.
Measurements:-

Description :-Shell small (L: 5.5 mm.
II: 6.0 mm in holotype), trigonal, inflated, slightly longer than high or as longLH
Th 11/L Th/L
L. (MM. 30~18) 15mm !Omm 4mm 0. 67
0.27
L. (l\'IM. 3099) 14
0.57
8
5
0.36
L. (MM. 3100) 15
9
0.60
0. 33
L. (MM. 3101) 12
6
0.50
3
0.25

"

Observation.·- There are se\·eral speci.
mens of internal and external moulds.
The elongate trigonal form is unusual.
The hinge area can not well seen because of the int1ated umbo in the inter·
nal rr.ould.
Comparison :-Some deformed specimens of Corbula globosa are similar tothis species but more globose and havedistinct rostrum. The internal marginal denticula:ion is absent in globosa.
This species is distinct from Opis (Tri·go11opis) torinosue11Sis by its low shapeof the shell.

as high; posterior margin straight;
anterior margin concave: ventral marginrounded: umbo sub-median or slightly
anterior, prosogyrate and strongly in·curved: lunule deeply excavated, cor·date. bounded by angulation, divided bymedian groove, smooth: escutcheon
defined by angulation, small and indis·
tinct; surface ornamented by about 30
elevated concentric ribs which are
regularly disposed and much narrower
than their interspaces: internal margin
not crenu!ate. A steep tooth belO\vumbo in right valve.
Obsercation and Co111parison :-Several
specimens of internal and externalmoulds at hand. The lunule and es·
cutcheon are strongly depre~sed andhounded by t\YO carina-like angulations.
The angulations become steep ridges
hut not carina. The absence of carina.
bis:-cted lunule andlanceolate escutcheon
are disti net specific characters.
This resembles Opis (Trigonopis) coral·tina D:\!\JON (ARKELL, 1932) at a glancein surface ornaments. It is distinguishe:d from that species by its distinct
deep lunule and lack of distinct carina.

Occurrence :-Loc~. 4, 11.
Family Erodonidae
Genus Corbu!a BRUGL 1i:J~E, 1797
Cm·bula globosa TAMURA, new species
Plate 1:!, Figures 1-4.

Dcscripjio11 :-Shell small for

genus.

365.

Upper Jurassic Pelecypods

prominently inflated. globose, inequilateral. nearly equivalve. trigonallyovate in outline; anterior margin short.
nearly straight or a little arcuate: posterior margin long and rostrate: ventral
margin a little rounded or nearlystraight: umbo at about anterior 1/4.
slightly incurved, prowzyrate and indistinct: sharp carina bounding depressed posterior area: surface with fine,fairly regular concentric ridges distinct
on antero-ventral side but obscure inother part: a strong fang· like cardinal
tooth in right valve and a socket inleft valve: marginal fiat belt distinct,
nearly parallel to shell margin: adductor scars strongly impressed on flat belt
in which posterior one is much stronger
than anterior.
i11easurements :L

H

Th
H/1 Th/Lmm
mm mm
R. (MM. 30!13) !J. 0
6. 0
2.5
0.67 0.~8
L. (MM. 309·1) 7. 0
O.IH
0.43
4.5
3.0
L. (MM.3095) 9. 0
6. 0
2 5 0.67 0. 28
L. (MM. 3096) 3.5
0.43
1.5
1.0
3.5
L. (:'vll\·1. 3097) 3. 0
1.0
0.43
3. 0 1.5

Observation :-Many external and in·ternal moulds of both ,·alves are variable in shape. although some are moreor less deformed. It is note-\vorthy thatthe H/L and Th/L ratios are larger insmall forms than in large form. Thismeans that the shell becomes less inflated and rostrum is more distinct inlarge form (prob<).bly adult form) thanin the small form (probably young form).
Comparison:- The internal wide belt
along the shell margin and the rostrum
are characteristics of this species.
Corbula is!ipensis LYe. (lVloR. and LYe.
1853, pl. 37. fig. 7) is closely related tothis species hut the umbo is more anterior in the latter than in the former.
Another similar species is Corbula borneensis VoGEL from Borneo (VoGEL. 1896),

115

but in bomeensis the position of umbo
is nearly mesial or slightly anterior
and the flat bell is not so wide as inglobosa. Corbula daglumiensis Cox from
Callovian of Somaliland (Cox. 1935) isclosely alike to this species hut in thelatter the rostrum is more developed
and the umbo not so elevated.
Occurrence :-Locs. 4. 5, 11. 12.
Family Lucinidae
Genus Lucina BRt:Gl:TERE, 1797
Lucina tsunoensis KI!\tL·R.-\
Plate 12. Figures 21. 22.
1956.

Lucina fstmoensis. KI:o-.tL:RA. p. 87. pl. 1,

figs. 11-13.

Fine concentric ridges are fairly regularly disposed and about 18 in number. Some specimen from Tsurubami
is large (20 mm long and 14 mm high)for the species and shows elongate
outline. Lucina s. str. in recent taxonomy has no teeth but Lucina s. I. in thispaper includes the one having teeth.
Occurrence :-Locs. G. 11.
Family ?\eomiodontidae
Genus Eomiodmz Cox. 1935
Eomiodon kumamotoensis T.\:o.tuRA.
new species
Plate 12. Figures 17, 18.

Description :-Shell medium to small
for genus. fairly convex, inequilateral.
somewhat quadrate and higher thanlong: umbo distinct. a little prosogyrate
and placed at a little anterior to center:
postero-dorsal margin a little rounded;
antero-dorsal slightly concave: ventral
rounded: lunule depressed and disnnct;
posterior surface bounded by obtuse

116

11£i1wru T:lMT.JRA

carina-like angulation, a little depressed: surface covered by 9 concenl ric
regularly disposed ridges: :! diverging
cardinal teeth and an anterior shortlateral tooth seen in left valve.
Jl;Jeasurements :R. (:M11 3105)
L.

(MM 310-1)

L
13.5 mm~}. 5

H
15.0 mm
9. 5

Obsen•ation :-There are a few internaland external moulds of both valves. but
the hinge area is poorly preserved andany precise observation is ditlkult. The
posterior cardinal tooth is much stronger than anterior one in left vaive.
The posterior depression on surface
happen to be impressed on an internalmould \Fig. 13} and the carina isdistinct.
Comparison:- This is closely allied to
Astarte altissima Co-. (1935) from Somaliland jurassic in external characters, but
in the iatter the internal margin isdenticulate as in many Astarte. Eomiodon
vulgaris HAYA~tt (1958) from the Liassic
Kuruma group is somewhat similar tothls but the concentric ribs of this are
more regular, smaller in number. The
shell of t•u!garis is more elongated than
this.
Occurreuce:- Locs. .!, fi.

Genus Eorrrl!ista DoL'VJI.I.f~. 1913·• Encallista ·· regularis T.,~tt:R.~.
new species
Plate 12. Figures 8-10.

~

Description :-Shell of medium size IL:
26mm. H: 20 mm), inequilateral, moderately convex, ovate and longer thanhigh: umbonal region slightly inflated;umbo a little anterior to center. prosogyrate, a little projected above hinge
margin: postero-dorsal outline rounded :posterior portion expanded and posttrodorsal outline sloping down to rounded
postero-ventral margin: ventral margin
slightly rounded: anterior marginronudecl and convex. its most anterior
part at about the mid-height: anterodorsal margin excavated: surface ornamented with about 40 fairly regularfme grooves: in right valve 1 welldeveloped. 3b long and not bifid, AI and
1'1 present (See Text-fig. 1).
ObserNrtion :-The holotype left valve
is represented by an internal and external mou lei. Its hinge structure belongs
to the Cyprinidae and is similar to one
of Eocallista. In Eocal/ista, however, 1
is not apart from AI (Cox. 1947}. Thisis more developed in h:nge than Eocallista but 3a is invisible.
Comparison :-An undi ffuentiated tooth of 1 and fairly regular concentric
tine grooves are characteristic of thespecies. Eomiotlon lmmamotoensis TA~tl'RA and Lurina tsrmoensis Kt:-tuRA
have fine, concentric. regularly disposed
ridges. These ornaments are somewhat
similar to those of this species, butthey are different in other characters.
Occurrence :-Loc. 5.

,.. Ptt?

1

Text-Figures 1. 2. 3.
Fig. 1. Hinge structure of a right valve of ·• Eocallis!a" regularis TAr-.tut~A, new species.
Fig. 2. Hinge structure of a left valve of :lnisocardia sp.
.
. 3. H'1ngc structure of a right ...-alve of Tancredia elmzguta T.-\~tCRA, new spectes.
F lg.

36 5.

Upper Jurassic Pelecypods

111

Family Tancrecliidae
Genus Anisocardia M~;:-;IER­CHAUIAs, 1863

Genus Tancredia LvcETT. 1850

Anisocardia sp.

Plate 12, Figure 23.

Tancredia rostra/a T.'-:-H.:RA,

Plate 12. Figures 19, 20.

Description :-Shell medium for genus(28 mm long. 14 mm high). slightly con-

Description :-Shell small to medium
for genus. moderately inflated. slightly
inequilateral. elongately subrectangularin outline; dorsal margin nearly straight,
almost parallel to ventral margin. anterior and posterior margins slightly
rounded and posterior one longer thananterior: umbo fairly elevated. a little
projected beyond hinge margin. prosogyrate and slightly incurvcd. situatednearly mesial: lunule fairly deep but
small: carina from umbo to posteroventral margin sharp and distinct:
surface ornaments unknown.
!1leasurements:L.
L.

t:\IM 3108)(:\IM 3109)

L

H

15 mm

13mm

18

14

Obserl'ation :-Represented by two internal moulds of left valYes having
Anisocardian hinge (see Text-fig. 21. It
some\vhat resembles .4nisocardia elega ns?-.·lc:-;IF.R-CuAI.:>IAS in hinge structure(Cox. 1947). but more or Jess deviatesfrom the latter. The specimens are
more or less deformed and the carina
in Fig. 15 is strengthened by deformation. The external characters are unknown.
Comparison:- The fairly long andstraight dorsal margin is characteristicof this species. Anisocardia tcilliamsoni
Cox from Scarborough Limestone inEngland (Cox. 19-!7) resembles thisspecies in general form but the umbo
is more elevated in the former.
Occurrence :-Loc. '1.

vex, highly inequilateral, ovately subtrigonal and much longer than high;umbo central. slightly prosogyrate, contiguous: antero-dorsal margin a little
arcuate. somewhat acutely tapering;
anterior extremity forming an angle ofabout 50" and a little higher from themidheight: postero-dorsal margin slightly rounded but angu late in middle partand shouldered; posterior extremity
somewhat angulate at junction withventral margin, at a little above midheight; ventral margin rounded: surface
smooth except for fine growth-lines: a
cardinal tooth below umbo in each valve
oblique; lateral tooth in left valve short:probably two laterals on right valve.
Comparison:- The outline and hinge
structure in Infra-Liassic species of
Hettaugia by TERQL'El\I which are now
included in Tancredia has angular outline and shouldered posterior-dorsal
margin (TERQLE:o.I. 1855). In outline,
this species is very elongate and acutely tapering anteriorly. The positionsof both shell extermities are at a little
higher than the midheight. These are
distinction of this species from otherspecies of Tancredia.
Occurrence:- These specimens from
Locs. 6. 1:2.
Family Pleuromyidae
Genus Pleuromya AcAssiz, 1843
Pleummya ? punctostriae TA:>IURA,
new species
Plate 12. Figures 29-32.

Afinoru TAMURA.

118

Description :-Shell medium to small
for genus (Holotype: 34 mm long. ~5 mmhigh). depressed, inequilateral, somewhat
rectangular or ovate in outline and gaping posteriorly: umbo at about anterior
1/4. not distinct. orthogyrate: posterior
dorsal margin truncated or slightly
rounded: posterior margin rounded anda little produced: ventral nearly parallel
to dorsal margins and rounded: wrinkles
on surface fairly regular and concentric:
radial rows of minute granules very
numerous on surface: hinge unkno\vn.
Obserl'atioll :-Several
internal andexternal moulds of both valves are
suffered from deformation. Figs. 29-31
are depressed laterally and Fig. 32
vertically. The posterior gape and thedistinct carina of Fig. 32 are strongly
exaggerated by deformation. As thehinge structure is invisible from thespecimens at hand. it is difficult to say
whether this belongs to P/eurom:ya or
to [Jomomya. judging from the modification of granulated surface of the
11yacids (;\loRRlS and LYcETT, 1853), thisbelongs rather to Pleuromya than !lomomva.
- -Comparison:-Homomya hortulana Ac.

from the Portlandian of Porrentruy(AcASSlz, 1840) resembles this species
in concentric wrinkles on surface andgeneral outline. But in the strong
inflation of the shell this is difference
from the depressed form of P. ? punctastriae.
Occurrence:- Loc. 4.

Description :-Shell small for genus.
fairly convex. equivalve, inequilateral.
trigonal in outline; umho situated nearly posterior end, nearly orthogyrate. not
inflated; postero-dorsal margin a little
arcuate and long; anterior margin slightly rounded: ventral margin rounded:
posterior area depressed; surface ornamented with about 12 discontinuousradial ribs or rows of tubercles but
absent on anterior side: growth-lines
coarse on ventral side: hinge unknown:
test thick.
A1easureme1lls :R.
R.

(MM 3119)(Ml\1 3120)

L
35mm

22

H
32 mm
20

Obsen•ation :-This species resembles
the Trigo11iae in its trigonal form andi1s thick test (2 mm in the holotype
specimen). The posterior margin isabsent and the postero-dorsal margin
directly joins with the ventral one. The
hinge structure is invisible hut probably not of the Trigoniae. The fine radial ribs or radial rows of tubercles arevery similar to those of P/zo/adomya.
So the writer includes this species in
J>holadomya. On the ventral side. tubercles are more distinct than in otherpart. especially at junction with concentric lines of growth.
Comparison:- This is distinctly different from other Jurassic species by its
trigonal shape and its discontinuousradial ribs. judging from the materials
aYailable for the writer.

Occurrence :-Loc. 1~.

Family Pho!aclomyidae
Genus Pholadomya G. B. SowERBY, 1825
Pholadomya ? ashikitcnsis TAr-.wrL\,

Genus .4rcomya AGAssiz. 1843
.4rcomya ? sp.

new species

Plate 12. Figures 24. 25.

DJatc 12, Figures 26. 27.

Two deformed internaliJloulds of left

T AMURA :Upper Jurassic Pelecypods

Plate 12

7

6

11
4

9

10

23

27

365.

Upper Jurassic Pelecypods

119

Explanation of Plate 12
Corbula globosa TA~lURA. new species
Fig. 1. Plaster cast of the external mould of the holotypc right valve; Loc. 4. x2.
(MM 3093)
Figs. 2. 3. Internal moulds of left valves; Loc. 5. X3. (MM 3094. 95).
Fig. 4. Internal mould of a left valve: Loc. 12. x3. (l\IM 3097).
Opis (Coelopis) tanourensis TAMC:RA. new species
Fig. 5. Clay cast of the external mould of the holotype left valve; Loc. 12. x3.
(MM 3091).
Figs. 6. 7. Internal moulds of the holotype left valYe: side view (Fig. 6) andanterior view (Fig. 7): Loc. 11. x3. (l'vi.M 3091).
" Eocallisla" regular is TAl\tuRA, new species
Figs. 8. 9. Clay cast of the external mould and internal mould of the broken holotype
left valve.; Loc. 5. x 1. (MM 3107).
Fig. 10. Internal mouid of the holotype left valve: xl.5.
Opis ( Trigonopis) toriizosuensis KIMURA
Fig. 11. Right valve; Loc. 6. x 1. (Ml\<I 3087).
Fig. 12. Internal mould of a left valve: Loc. 6. xl.5. (MM 3089).
Fig. 13. Intetnal mould of a right valve; Loc. 6. x 1. (i\llVI 3088).
Opis ( Trigonopis) trigona/is TA~IURA. new species
Fig. 14. Left valve; Loc. 6. x2. (MlVI 3098).
Fig. 15. Internal mould of the holotypc left valve: Loc. 4. x 2. (MM 3099).
Fig. 16. liiternal mould of a left valve: Loc. 4. x2. (i\I::VI 3100).
Eomiodon kumamotoensis TAMl:R.\, new species
Fig. 1/. Inte-rnal mould of a right valve; Loc. -1. X3. (l\Uvi 3104).
Fig. 18. Plaster ca~t of the external mould of the holotype left valve; Loc. 6. x2.
(M:t\'1 3105).
Anisocardia sp.
F~gs,· i9, 20. Internal moulds of !eft valves; Loc. -!. X 2. (NEVI 3109, OS).
Tani:redid_ rostmta TA!vtt.:RA. new species
Fig. 23. Internal mould of the holotypc left valve; Loc. 6. xl. (l\IM 3110).
Luci11a lswzoensis KI!\IURA
Fig. 21. Clay cast of the excernal of a left nlve; Loc. 11. x3. (.MM 3.102).
Fig. 22. Left valve; Loc. 6. X 1. 5. (MM 3103).
rlrcomya ? sp.
Figs. 2!. 25. Internal moulds of left valves; Locs. 11 (Fig. 24), 4 (Fig. 25). x:!. (MM3121. 22).
Phaladomya ? ashikitensis T.'\:\ll:RA, new species
Figs. 26, 21. Internal mould and the modeling cast of the external mould of theholotype right valve; Loc. 12. xl. (M:\1 3119).
Goniomya sp.
Fig. 28. External mould of the fragment of a right valve?: Loc. -1. X 1. C'I:VI 3123).
Pteuromya ? Pllllcfostriae TA:O.IC:RA, new species
Fig. 29. Internal mould of a right valve: Loc. 4. x 1. (l\Ii\1 3112).
Figs. 30. 31. Plaster cas~ of a external mould and internal mould of the holotype
right valw; Loc. 4. x l. (lVIM 3113).
Fig. 32. Internal mould of a bivalved shell: posterior view: Loc. '!. x 1.5. (MM 3114).
All specimens here described are stored in the Geol. Inst.. Univ. of Tokyo.

111inoru TAMURA

120

valves at hand are probably included
into Arcomya due to its general resemblance to Arcomya and the lack of tooth.
Shell small. inequilateral. a little convex. elongately ovate in outline: umbo
a little anterior to middle. incurved andprosogyrate; posterior and ventral mar·gins rounded but posterior produced
posteriorly; anterior dorsal margin excavated: anterior margin truncated.
Occurrence :-Locs. 4, 12.
Genus Goniomya AcASSIZ, 1838
Goniomya sp.
Plate 12. Figure :!8.

Two fragments showing characteristic
V-shaped ornament of Goniomya are at
hand.

Occurrence :-Loc. 4.
References cited(18,!0-45), Etudes critiques sur
les !viollusqucs fossiles.
Cox. L. R. (1941). The Lame IIi branch Fami·ly Cyprinidae in the Lower Oolires ofEngland. Proc. Jllalac. Soc. London. Vol.
AGASSIZ. L.

27. Pt. 4.
I. (1958),

A Review of the socalled Liassic .. Cyrenoids" in Japan.
]ap. four. Geo/. Geogr. Vol. 29.
VOGEL. E. (1896), Molluskcn aus dem Jura
von Borneo. Samml. Geo/. Reichs·,\Jus.
Leiden. 1. Ser. Bd. 5.
See also ARKELL (192'i-3i). Cox (1935),
Knn;RA (1956), MoR. and LYC. (1854),
TA:<.!URA (1959-1. -2) in Bibliography ofTrans. Proc. Palaeonl. Soc. ]apa11, N. S.
Nos. 33, 34 of this study.

HAYA:<-11.

Trans. Proc. Palaeont. Soc. Japan. ~- S .. No. 35, pp. 121-132. pl. 13, Sept. 15. 1959::J()G.

ON THE l\IIOCE~E PECTINIDAE FRO.l\1 THE EN\'IRO~S OF
SENDAI: PART 15. PECTEN COSJBENSIS YOKOYAMAAND ITS RELATED SPECIES*
KOICHIRO MASUDA
Department of Geology, Faculty of Education. Tohoku University

flllf:tllf-ti!IIfl~*lt@ Pt:ctinidae: ~ 0) 15, Pecten cosibensis YoKOYA'\IA &U ~ 000~
Njl::. "?l 'L: Pecten cosibensis YoKOYA'\!A t.ti!HJJM!#HII~0!]'~~iJ· ~lie~~~ tL. #tt"dtl!:b•~ ~ <O)JM~iJ=¥!H~r ~ ttt~. Ui' L ~ O)/~~JaifiXiJCf1C5tL'<f1 ?t: u; ~::.;lf:m:::. ~ <0ilt\i!;t:b:(t: t.-ct't~. 1!:?H:t cosibensis &O:ctt:::.IJ;H:~t'<0)~;$:1C?P"'Cj]}~iHL. cosibensis 0):7'A7 f'e(AO) 4 "?O)!IfifiJil:.[~jJij J.., t:. -e tL ':)It~'< Clilamys cosibensis cosibensis (YOKOYA~IA),
Clz. cosibensis hanzawae !lk\SliDA. n. subsp .. Ch. cosibensis turpicula (YOKuY:\~tA),
C/z. cosibensis lzeterog/.lPia (YOKOYA:.tA) L' ,0 7.>. :. tl. ~ O)ff\Jr::. :t cosibensis lzanzatcae-.
cosibensis (s. s.)~cosibensis turpicula-~cosibensis lzeterog/ypta O)jfll ft~"YijiJ :;~ ;t ~ tL 7., ,1t1 rn lf: -· m;

at Kaidate. Sawada-machi, Sado-gun. 1\iigata Prefecture and stated that his previously described Pecten cosibensis is asynonym of P. heteroglyptus. But as
pointed out by Kt:RooA (1932) and !\olltuR,, and HATAr (1936), such procedure
is not favorable. GRA:'\T and GALE (19311
regarded YOti:OY A :.r .\ 's cosibensis and tigerrinus to be synonym of Pecten (Pallium)su•iflii var. etclzegoini AxDEt~so:-; and YoKOYA:.tA's heteroglyptus to be Pecten sw1ftii
var. nutteri ARxOLo. The writer (MS)holds the Japanese species as distinct.
No~tt:RA and H,\TAr (1935) described anddiscussed P. cosibensis and P. heterog(lPtus from the Pliocene Daishaka formation near Daishaka, Namioka-machi, Minami-Tsugaru-gun. Aomori Prefecture.
but confusion still remains concerningthem and their related species.
Numerous specimens of P. cosibensis
were studied and the results show thatthe cosibensis group includes four subspecies. Clilamys cosibensis (s. s.). C!z. cosibensis lianzazcae JYL,.suoA. n. subsp., Clz.

Introduction and Acknowledgements

The type specimens of Pecten cosibensis
YoKOL\:.t:\ (1911) from the Pliocene Koshiba formation at Koshiba. Yokohama
City, Kanagawa Prefecture consist of
two unfavorably preserYed shells. The
one described as a left \"alYe is a rightvalve. His Pecten tigerrinus Ml'l.LER fromthe same locality are the left ,-ah·es ofcosibensis. and his Pecten sll'iftii (Yo~-;o­YMtA, 1920) from the same locality is aright valve of cosibensis. Cosibensis also
occurs from the Pliocene of Saishu
Island (YotwYA~rA, 1923). The Shigarami
Miocene at Shimosoyama. Shigaramimura. Kami-:\linochi-gun, Nagano Prefecture, yielded him an imperfect rightvalve of Pecten turpicu!us; it is close tocosibensis. He described !1926) Pecten
Jzetemglyptus from the Sawane Pliocene* Received Oct. 14. 1958: read at the 7lst.
meeting of the Society at Kyoto, Sept. 27,
1958.

121

122

Koichiro MASUDA

cosibensis turpicu!a and C/z. cosibensis Iiefer·oglypta.
Acknowledgements are due to Dr. Kotara I-L... TAI of the Department of Geology, Faculty of Education, Tohoku University, for his supervision. Thanks are
due to l\iessrs. Yutaka SAITo of the Department of Geology, Faculty of Education, Shinshu University, Shin-ichi Ho:-;:-IA of the Kanaza,\·a High School at
Kanai-mura. Sado-gun, Niigata Prefecture and Jun K ..n ..-.oKA of the Instituteof Geology and Paleontology, Faculty of
Science. Tohoku Lniversity, for theirassistance in the collecting specimens.
Description

Family Pcctinidae
Subfamily Pectininae
Genus Chlamys (BoLTE:-;) RonJ:-;G, 1798

Clzlam_vs cosibeusis (YoKOY\\lA). 1911
Plate 13, Figures 1-9.
1911. Pecten cosibeusis Yoi\OYA\1.-\. ]our. Geol.
Soc. Tokyo, Vol. 18, No. 208. p. ·L pl. 1,

figs. 3, 4.
1911. Pecten tigerrimts 1\Iiil.LER. YoJ\OYA\1.-\,
Ibid., p. 3. pl. l, figs. 11, 12. (non .tvHiL·
LER, 1ii6).
1920. Pecten cosibeusis YOKOYA\IA, four. Col/.

Sci., Imp. Univ. Tokyo. Vol. 39 . .4rt. 6.
p. 156, pl. 13, figs. 7. 8.
1920. Pecten su·iflii BERl'ARDI, YoKOYA\1.\,Ibid .. p. 15·1, pl. 14. fig. 11. (non BER·

:o;ARDI. 1858).
1920. Pecten tigerrinus }.[i.iLJ.ER, YoKOYA~IA.
Ibid., p. 155, pl. ].1, figs. 5. 6. (non l'vli.iL·
l.ER, 1716).
1923. Pecten cosibensis YOKOYA\1.·\, Ibid., Vol.
44, .-lrt. 7. p. 7. pl. 1. fig. 5.
1926. Pecten heteroglyptus \·ar. cosibensis YoEO·
YA!\1.-\, .Tour. Fac. Sci., Imp. Uniz·. Tokyo,
Sec. 2, Fol. 1. Pt. 8. p. 30-1. pl. 33, J1gs.
6, 7.
1930. Chlamys cosibcnsis '( OEOY.-\\IA, Kt:RODAin Ho:-;\1.\, Ceo!. Cent. Shina11o. Pt. 4,
p. 36, pl. 3, fig. 12.
1935. Chlamys su·iftii etchegoini (A;-.;oERSO:-J),
0TUKA, Bull. Earthq. Res. Inst .. Vol. 13,
Pt. 4, p. 886, pl. 55, fig. 1-10. (non AN·
DERSO:'-i, 1905).
1935. Pecten (Pallium) cosibensis YOKOYA:-.J,\,
xo~Jl'R.·\ and HATAI. Saito H0-011 Kai.l/us., Res. Bull., No.6, p. 9i. pl. 12. figs.
5. 8, 9: pl. 13, figs. 4-1.
lY53. Pecten (Paffium) heleroglyplus YoKOYt\·\!A. ::\0\ll.'llA and I·L\TAI. Ibid.. p. 99,
pl. 11. fig. 7. (non YoKOYA:<.IA, 1926).
1950. CIJ/amys islandica var. su:iftii form etdle-

goini (AI"DEHSO!\). Kt;BOT:\, Cenozoic
Research, So. 6', p. 15. pl. 8, fig. 5c!; pl.
9, tig. 68. (non Ar-;DERso:-;, 1905).
1950. ChlamYS is!andica var. cosibensis YoKO·
L\~1:\, Kt:HOTA. Ibid .. p. 15. pl. 8, fig.
55.

Shell moderate in size, thickness andconvexity, higher than long, equilateral
except for auricles; left valYe moreconvex than right: ventral margin some·\\'hat uneven corresponding to exte:rnal
sculpture: both valves radiate!~· ribbed
and forming an angle of less than 90"
at apex.
Right valve with more than :::!0. roundtopped, unequal radial ribs. fine intercalary threads and concentric growthlines. with rather distinct fine network:radial ribs in central pan of disc usual·ly gathered into four, rather eleYated,rounded, stout fascicu Jar bundles separated by more or less deep valleys, usually divided into two parts by a shallow
longitudinal furrow near beak and some·times again near ventral margin, butsometimes \·alleys so shallo\\. that fascicular bunclies become rather inconspicuous: two fascicular bundles in central
part of disc much more distinct thanothers, usuallv consist of four to fiveor rarely more, subequal radial ribs
more or less broader than interspaces,and sometimes with an intercalary thread

366.

Miocene Pectinidae from the lilwi1·ons of Sendai

between them. but bundles near submargins usually rather inconspicuous
and with a few intercalary threads between radial ribs; submargins withseveral. subordinate, fine radial threads;
valleys usually rather deep, narro\verthan bundles themselves and with unequal intercalary threads which are twoto three or rarely more in number:primary intercalation usually appears
on upper half of disc. nearly equal todivided threads in strength at ventral
margin; secondary and tertiary intercalations appear on lower half of disc, andsomewhat fainter and finer than otherradials; concenl ric constrictions rather
distinct: anterior auricle much larger
and longer than posteri'Or one, furnished with deep byssal notch and rather
narro\v byssal area. and sculptured withseveral. dis! inct. somewhat imbricatedradial threads, fine intercalary threads
and concentric lines: posterior auricle
similar to anterior. though radial threadsof posterior one more numerous and lessdistinct than anteriors: hinge with distinct cardinal crura, rather wide andshallow resilial pit provided with distinct lateral ridges \Yidely open towards
lower, and with distinct ctenolium. Leftvalve with five, prominent. rather stout
radial ribs se!Jarated by rather deep andwide valleys, rather low, fine radial ribs
in valleys, fine intercalary threads andconcentric growth lines. with rather distinct fine network: ribs prominent. twonear submargins sometimes inconspicuous, nearly equal to others in strength
near beak but tend to become stout andelevated towards ventral margin. divided into three or more. finely scaled,fine radial threads by shallow longitudinal furrows: other radials unequalin strength, finely scaled. and rarely
divided into two finely scaled radial
threads by a shallow longitudinal fur-row: intercalary threads between radialribs finely scaled, usually appear on
upper half of disc, and sometime secondary ones between radial ribs and intercalary threads appear near \'entral margin: concentric constrictit'llS usuallymore distinct than those of right valve,and sometimes radial ribs appear somewhat nodose: anterior auricle sculptured
with a fe\v finely imbricated. fine radial
threads and concentric lines. posterior
one similar to anterior. though radial
threads more numerous and finer thananteriors. Interior surface of yaJves
gently folded corresponding to external
sculpture: characteristic fine serration
at ventral margin.
Dimensions :-Shown in Table 1.
Comparison and Afjillily :-Ciilamys(Swiftopecten) su:iflii (BER:'o:ARnl'i is dist ingu isheel from the present one by its
large. posteriorly contorted shell which
is much higher than long, smaller apicalangle. triangular anterior auricle. rather
simple cardinal crura and rather 11athinge plate sculptured ·with fine striae
parallel to the hinge line. and nearly
11at left valve in young shell. Chlamys
wattsi (AR:o.~OLD) (AR:o.~ow. Hlflf5, from the
Pliocene of Fresno County and Ch/amyszcaftsi 1110ra11i (ARNOLD) (AR:'o:C>LD, 1906)
from the Pliocene of l'vlonterey County.
both in California. resemble the present
species: the former differs from cosibensis by its right valve having convexity nearly equal with the leit valve,radial ribs. less prominent byssal notchand obsolete posterior auricle. and fromthe latter by its radial ribs with five toseven. strong, squarish, elevated radial
threads. slightly developed byssal notch,
short posterior auricle and less distinct
concentric constrictions. Chlamys etc/wgoini (AiXDF.:RSO:-.:) (.\'0~11-Ai':D, 19lo) fromthe Pliocene of Fresno County, California. resembles this species, but differs

Koichiro MASUDA

124
Table 1.

Measurements on the selected specimens of cosibensis group (in nun.)

.z
~

A

I

I

24

21.5

10. 5 . 6

-18.8

45

19. 4 I 107
3531.7 15. 5
26. 1 :!3. 7 12. 7 I 5.
25 . 22.2 1:!
4
24. 6 21. 5 1 L 5
4. 3
37. 8 3416
8. 5
31. 9 28. 1 146
31. 2 2'1. -1 14
5. 4
27. 5 241:!
5
25, 2 22. 3 12. 5
4. 7
c 56. 5 54. 3 24. 3 8. 9
55. 8 51. 3 22 I 11. 2
53.1 46. s 20.5
9. 5
1!!
10. 8
47
43
13
s
34.4 31
. 58
52. 5
l'l
20
16
51. 3 41
15
10
39
35
6
28.8 24.7 12.5
ll, 8
6, 7
26
22
15.5
D 66. 2 58. 4 26
'11.6 38.2. 1!!
10. 7
Hl. 2
74.2 70. 4 30
58.8 5122.7 14.6
8. 8
1-17
E 37

85'
85'
80'
85"
85"

80'

11. 5
10 8
9 5
9. 6

R

IF

,.

80'
80'
80'
85'
80'
85"
80'
80'

bC

I
I

I

"

c:

j

::!:

19.5
17 ·7

18.8

10.2
8
10.8
10.2
10.5

§
~

I

I

L

"'

1

H
E

R

I

~I
;:::

I

·~

I

~
_::

I

I

;.; I
I

L

R

s

90"

R

6.4
5

90'
90'

5

90'

...-

ce
u

0.

·-

I c5

.('

5
4
5.3

90'
90'
90'

9.2

6.3
4. 3
4.1

90'
90'
90'

9.5
11

4

5. 5

90' 1 "
90' ' R?__ ;)
-

90'

s

90'

c

1·1. 8
32

13. 7
30.4

46

-12.5 17.5 12. 5
34.3 16.4
7, 5
I
34.3 16.4 1 7. 8
7
34
I
31
14
6. 5
38,2 16.3
8. 2

39.7
39.7
37.4
35.5
44,3

60
' 55
49

28

85,
85'
85'
90'
85'
80'

C.>1.c

t>0

c:

16.5
26.2 24.5'§
24. 2 22
22
20. 5
I
20.
2 18
-:;: I. 18. 1 16. 4..;
G 28 ' 26

85'
85'

-:5

;I;

-- ----------'--

85"

I

31
I 29. s26. 4 24. 5
23.7 21.3
21
19. 5

!

1~1....11 ~

80"

I

I

F

80'
85'

..c:
ac

g

1.l

B

C)

...
ce

·;:;

---------

1:

~

R

"
L

13

57
56. 5
53. 5
36
74. 2
62.5
74
66.5
34
34

55
50.9

46
25 7
52.2
51
48. 6
31. 7
71. 5
59. 5
69
6-L 7
30
30

23
22

19

I

90'
85"
85''

13

29
15.6
15.6

18.8
19.5
6. 1
7.2

4.8

L
I "
I "

!

I

R

I'+
L+
R

85'
85'

1

L
R

85'

10.3. 90'
8. 6
90'
9
90'

12.4
21
22
21. 5
14. 4
29. 8
28

R

,

L

R
I

90'

13.4

90'

L

lL

90'

II

12

90'
90'
90'
90'
90'
90''

6.5
15. 2

ss·
85'

"
"
R
II

L
1

I

R+
L+

+ ..... intact valYe. A ...... Koshiba formation. Kanagawa Prefecture. B ...... Jiamada formation,
Aomori Prefecture. c ...... sawane formation, Niigata Prefecture. o ...... Daishaka formation,
Aomori Prefecture. E ...... shigarami formation. Nagano Prefecture. F ...... sugota formation.
Akita Prefecture. G ...... :.\[oniwa formation. Miyagi Prefecture. H ...... Qtsutsumi formation,
Miyagi Prefecture. r ...... suenomatsuyama formation. lwatc Prefecture.

366.

i'vfiocene Pectinidae from the Environs of Se11daiby the radial ribs and the obsolete pcsterior auricle.
Remarks·- This species which is characterized as above described are fromthe localities nientioned below.
Described sPecimens :-River cliff of the
Chikagawa stream, about 200m. fromthe sea shore at Chikagawa, Tanabumachi, Shimokita-gun. Aomori Prefecture. Silty fine-grained sandstone of
the Hamada formation (Pliocene). DGS.
Reg. No. 3686. IGPS, coil. cat. no. 1:2!1:16.
Occurrence :-Aoso, Nanakita and Ctsuno formations in Miyagi Prefecture.
Ginzan formation in Yamagata Prefecture. Suenomatsuyama formation in lwate Prefecture. Shigarami formation in?\agano Prefecture. Sawane and Shiraiwa formations in Niigata Prefecture,
Sasaoka formation in Akita Prefecture.
Koshiba formation in Kanagawa Prefecture. Hamada and Daishaka formations
in Aomori Prefecture and Setana formation in Hokkaido: Late Early \'liocene
to Pliocene in age.
Chlamys cosibensis lzauzawae
N! .,st:DA, n. subsp.
P 1ate 13, Figures 10-15.
19~:1.

Pee/ell suNtii BERNARDI. YoKOYA~IA.
}our. Fac. Sri .. Imp. Unir. Tokvo. Sec. ::!,
Fol. 1. 1'1. 3. p. 123. pl. 15. fig. 3. (nonBER'>ARDI, 1858).
1936. Pecten (Jianl/pecten) cnsiilensis YoKOYA·\lA. :\'o~IL'I<.-\ and HATAI. Saito Ho·mJ
Kai .\[us .. Res. Hull .. ""1\To. 10. p. 163, pl.
18. tigs. 5. 39--12.
193i. Pectm (Szciftopecten) su·(flii BERNARDI.
:\'o:-.lt'H."< and H:\T.•d. Ibid .. So. 13. p.
129. pl. 18. fig. 6. (non BF.R:"ARDI, 1858).

Shell small. inflated. suborbicular,
equilaterai except for auricles; rightvalve more convex than left; both
valves radiately ribbed and forming an

125angle of about 90' at apex.
Right valve with about 20. close-set,rather distinct. round-toppe:i. fine radialribs. finely scaled. fine intercalary threads
and concentric growth lines. with distinct fine net\\·ork: radial ribs in central
part of disc usually gathered into four.
round-topped, rather elevated. stout fascicular bundles separated by rather deep
valleys. usually divided into two parts
by a shallow longitudinal furrow towards ventral margin; bundles of fourto six. suhequal radial ribs broader thantheir interspaces and sometimes finely
scaled, sometimes with a fine intercalarythread between radial ribs; submargins
sculptured with several. subordinate,faint. fine radial threads; valleys usually rather deep. narrO\ver than bundles
themselves. with unequal intercalarythreads which are one to three or rarely more in number. sometimes valleys
very shallows and narrow; primary intercalary threads usually appear on upper half of disc. nearly equal to divided
radial threads in strength at ventral
margin, secondary and tertiarY interca!aries somewhat fainter and finer thanother radials appear on lower half of
disc: when of inconspicuous bundles intercalary threads are one to three in
number. and fainter and finer than radial threads; more or less distinct concentric constrictions sometimes present
near ventral margin: anterior auricle
much larger and longer than posterior
one. with narrow and deep bys:;al notch
and rather narro\v byssal area. sculptured with several. distinct. more orless imbricated. fine radial threads andconcentric lines: posterior auricle similar to anterior, though radial threads
somewhat fainter and finer than thoseof anterior: hinge with very conspicuous cardinal crura. rather '"ide andshallow resilial pit with distinct, fine

12G

Koichiro M.4SFDA

lateral ridges widely open towards low·er, and with distinct ctenolium. Leftvalve \Yith about 20, fine radial ribs.
three in central part of disc prominent.
intercalary threads and concentric
gro'\\·th lines, with rather distinct fine
network: three prominent radial ribs
rather sharp near beak, subequel toother radials, usuallv tend to become
elevated. stout and rounded towards
ventral margin. and divided into three
to four or rarely a little more, finely
scaled radial threads by shallow longitudinal furrows: other radials finely
scaled, rarely divided into two, finely
scaled radials by a shallow longitudinalfurro\\·, and nearly equal to or a little
less than di,·ided radial threads of prominent radials in strength at ventral margin: intercalary threads finely scaled.
primary ones usually appear on ahout
half of disc. and secondary ones appear
near ventral margin: submargins sculptured with several, faint. fine radial
threads: anterior auricle with seYeraL
finely imbricated, fine radial threads andconcentric lines. and posterior auricle
similar to anterior in sculpture. thoughradial threads fainter and finer thanthose of anterior. Interior surface ofvalves gently folded corresponding toexternal sculpture: characteristic fineserration at ventral margin.
Dimen;::ions :-Shown in Table 1.
Compariso1l and Affinity:- This species
is distinguishable from cosibeusis (s. s.)by its small, suborbicular shell. themore inflated right valve, some\vhatlarger apical angle, rather distinct. fineradial ribs and indistinct concentric constrictions. Ch!amys (Sttiftopecten) stdftii(BER:-:ARr>l) differs from the present one
by its large, posteriorly contorted shell,smaller apical angle: radial ribs andvery large triangular anterior auricle.
Remarks :-The subspecific name is de-dicate:l to Dr. Sh6shir6 HA;-;zAwA. Professor of the Tohoku University in recognition of his contribution to thepaleontology of Japan.
Type locality, Geological formation and
Age :-ukibuta, Higashi-Yuri-mura, Yuri-gun, Akita Prefecture.
Lat. 39°18'05"N., long. HOo~W'05"E. Conglomeraticcoarse-grained sandstone of the Sugota
formation. Early rv1iocene.
Occurrence :-Sugota formation in Aldta Prefecture, M~niwa, Tsunaki. 6tsutsumi and Oido formations in l\1iyagi
Prefecture. Nanao formation in Ishikawa
Prefecture, Suenomatsuyama format ion
in Iwate Prefecture, and Obashira. Chich:bu City, Saitama Prefecture: Earlyto Late l\Iiocene in age.
Depositmy :_:_Holotype. DGS. Reg. ?\o.
3G90. Paratypes. DGS. Reg. ?\o. 3691 and
SM. Reg. Xo. /360.

Clzlamys rosibensis turpicu!a(YoEOYA:\IA), 19~6

Plate 13. Figures 16a. b.
1926. Pecten turpicufus YoKoY :\:\1.'\, ] our. F'ac.
Sci .. Imp. Unit•. Tokyo. Sec. 2. Vol. 1, Pt.
1. p. 18. pl. 2. fig. ~.
1931. Chlamys szciflii turpiculus (YOKOYA:\IA).
KuwoA in Ho:-::-.tA. Ceo!. Cent. Shina11o,
Pt. 4, p. 36, pl. 3. fig. 13.

Shell moderate in size and convexity.
higher than long, equilateral except forauricles, subequivalve: both valves radiately ribbed and forming an angle ofabout 85" at apex.
Right valve with more than 20, unequal. round-topped radial ribs, fine intercalary threads and concentric growthlines. \Yith rather distinct fine network;radial ribs in central part of disc usuallygathered into about ten, more or lesselevated, round-topped fascicular bundles separated by somewhat deep and366.

Miocene Pectinidae from the Environs of Sendai

narrow valleys. divided into two or
three parts by shallow longitudinal furrows near half of disc towards ventral
margin, other radials near subm2.rgins
rather low, divided into two parts near
ventral margin or remain undivided:
fascicular bundles usually of two unequal radial ribs. separated by rather
narrow and shallow interspaces with or\Vithout an intercalary thread; submargins sculptured with several. subordinate. faint, fine radial threads: valleys
rather deep. narrower than bundles.
with unequal fine intercalary threads.
one to three in number: primar)' intercalary threads appear on upper half ofdisc, nearly equal to divided radial
threads in strength at ventral margin,
secondary and tertiary ones appear on
lower half of disc : concentric constrictions rather distinct: anterior auricle
much larger than posterior. with deep
byssal notch and narrow byssal area,
sculptured with several, distinct. fineradial threads and concentric lines. appearing more or less imbricated: posterior one similar to anterior: hingewith distinct cardinal crura, distinct
ctenolium. rather wide and deep resilial
pit with rather distinct lateral ridges.
Left Yalve with prominent. round-topped. unequal radial ribs separated byrather deep and wide valleys, rather
low radial ribs in valleys and near submargins. fine intercalary threads andconcentric growth lines. ornamented by
distinct fine network; prominent radialribs nearly equal to other radials instrength near beak, but tend to become
unequally elevated and rounded towards
ventral margin, and usually divided into
three to four or rarely more. fine radial
threads by shallow longitudinal furrows.
sometimes radial ribs smooth and theirdivisions obscure: other radials rather
low. usually alternate with prominent1-')"'I

radials. and divided into two parts orremain undivided: submargins sculptured with seYeral, subordinate, fineradial threads: valleys usually deep orsometimes shallow, somewhat broader
than radial ribs: intercalary threads
unequal in strength. usually one tothree or rarely more in number: primary
intcrcalaries usually appear on upper
halt of elise. seconclarv ones on about
half of disc: concentric constrictions
rather conspicuous: anterior auricle
sculptured with several. more or lessimbricated, distinct radial threads, somewhat less distinct intercalary threads
and concentric I ines. and posterior one
similar to anterior. though posterior
radial threads much fainter and finer.
Interior surface of va!ves gently folded
and with characteristic fine serration at
ventral margin.
Dimensions :-Shown in Table 1.
Comparison and cl/finity :-This differsfrom cnsibeusis (s. s.) by its suhequivalved
shell. about 20, unequal. round-topped
radial ribs which are usually gathered
into about ten. more or Jess elevatedfascicular bundles in the right valve.
and the left vah·e with rather prominent.
rounded. unequal radial ribs which arealternated with the less prominent radialribs. It becomes difficult to distinguishthe present one from cnsibensis (s. s.).
when the latter has the radial ribs
separated by rather wide and deep interspaces with one or two intercalarythreads. Chlamys 111ttferi (Al~~oLo) (ARNOLD, Hl06) from the Pliocene of San
Mateo County, California, is distinguished from tmpicu!a by its larger shell.
smaller number of and more prominent
radial ribs and stronger intercalarythreads.
Described specimens :-Left river cliff,
Shimoniregi, Shimosoyama, Shigaramimura. 1\.arni-l\Iinochi-gun. Nagano Pre-

Koichir6 MASUDA

128

fecture. Fine-grained sandstone of the
Shigarami formation (Late Miocene).
Topotype. DGS. Reg. No. 3698.
OccMrence :-Shigarami formation in
Nagano Prefecture, Suenomatsuyama
formation in lwate Prefecture. Sawane
and Shirahva formations in Niigata Prefecture, and Daishaka and Hamada formations in Aomori Prefecture: Late;'vliocene to Pliocene in age.
Chlamys cosibensis heterog!ypta(YoKOLUJ.-\), 1926
Plate 13, Figures lia-c, l8a--b.
1926. Pecten lleterog/yptus

YoKoYAMA. four.
Fac. Sci .. Imp. Uni1·. Tokyo, Sec. 2. Vol.
1. Pt. 8. p. 304. pl. 33, figs. 1-5. 8.
1936. Pecten (Pallium) lzeterog/yp/us YoKOYA·~1:\, No~tt;RA and H.-\TAI, Saito Ho-on
Kai Mus., Res. Bull .. J'lio. 6. p. 99, pl. 10.
figs. 5. 6: pl. 11. figs. 1, 2.

Shell moderate in size. rather thick,suborbicular. equilateral except forauricles: left valve somewhat more convex than right: both valves radiately
ribbed and forming an angle of about
90' at apex.
Right valve with about 25, roundtopped, smooth, nearly equal radial ribs,
unequal fine intercalary threads andconcentric growth lines. with rather
distinct fine network: radial ribs broader
than their interspaces and divided into
two or rarely three parts by shallow
longitudinal furrows on lower half ofdisc; interspaces unequal: submargins
sculptured with several. subordinate,faint, fine radial threads: intercalarythreads usually one in number, but twoor three when interspaces widen, in
which primary intercalary thread appears on upper half of disc, and secondary or tertiary ones near Yentral margin; concentric constrictions sometimes

more or less distinct; anterior auricle
much larger than posterior. with narrowand deep byssal notch. rather narrow
byssal area, and with several. distinct
radial threads. fine intercalary threads
and concentric lines. giving imbricatedappearance; posterior auricle similar toanterior. posterior radial threads somewhat less distinct and more numerous
than anteriors: hinge with conspicuous
cardinal crura. rather deep resilial pit
with distinct lateral ridges and distinct
ctenolium. Left valve with round-topped, unequal radial ribs, fine intercalarythreads and concentric growth lines,
with tine network; radial ribs usuallydivided into two or rarely three, fineradial threads by shallow longitudinalfurrows towards ventral margin. someremain undivided: intercalary threads
usually one or rarely three in number,in which primary intercalary thread
appears on upper half of disc, andsecondary or tertiary ones appear near
ventral margin: concentric constrictionsindistinct: anterior auricle larger thanposterior, and with several, fine radial
threads, faint intercalary threads andconcentric lines. giving imbricated aspect; posterior auricle similar to anterior in sculpture. radial threads a more
numerous and fainter than anteriors.
Interior surface of valves gently folded
and with fine serration at ventral margin.
Dimensions :-Shown in Table 1.
Comparison and Affinity:- This subspecies is distinguished from cosibensis(s. s.) by its suborbicular shell, roundtopped. smooth. subequal radial ribs
which are not gathered into fascicularbundles. indistinct concentric constrictions in the right valve and by the left
valve having unequal. round-topped
radial ribs and indistinct concentric
constr ict:cns. Chlamys cosibensis turpi-

366.

Miocene Pectinidae [1·om the Environs of Sendai

cu!a differs from the present one by its
subequivalvecl shell, about ten, more orless elevated fascicular bundles consisting of about two, round-topped radialribs separated by rather deep valleys,conspicuous concentric constrictions in
the right valve, and by the left valYe
having rather elevated, round-topped,
unequal radial ribs separated by moreor less deep valleys and conspicuousconcentric constrictions.
It becomes difficult to distinguish thepresent species from cosibensis 1s. s.1 andcosibensis turpicula, when the valleys
between the fascicular bundles are shallow and the concentric constrictions are
more nr less i ncl ist i net in them.
Cli!amys erythmcomata (DALL) (DALL,
1907). a Recent Northern Pacific scallop,
is distinguished from the present one
by its rather large, thick, orbicular, inflated shell. more radial ribs which are
more or less squarish in form and gathered obscurely into fascicular bundles
and the inconspicuous cardinal crura.
Described specimens :-Right river cliff.
northwest of Daishaka, Namioka-machi.
~'linami-Tsugaru-gun,
Aomori Prefecture. Conglomeratic calcareous coarsegrained sandstone of the Daishaka formation (Pliocene). DGS, Reg. No. 3688.
Occurrence :-Sawane and Shiraiwa formations in Niigata Prefecture and Daishaka and Hamada formations in Aomori
Prefecture :-Pliocene in age.
Remarks nn Chlamys cosibensis
and its subspecies

As mentioned in earlier p:!ges, Chlamys
cosibensis and its subspecies are closely
related to each other. Their sequence inappearance is cosibensis lumzawae fromthe early Miocene, ·cosibe!tsis ts. s.) fromthe late early Miocene, c.osibensis turpicula from the late Miocene and cosi-

12!)

bensis lzeterog!ypta from the Pliocene.
Some specimens of cosibensis lzanzawae
fmm the Moniwa formation at Kita-Akaishi, Sendai City, occur associated with
Lepidocycli1Ut japonica Y.-\BE, pectinids as
Chlamys arakatmi (~o~WRA), Clzlamys nisataiensis On·r;A, Nanaochlamys notoensis(YoKoYA~L.,), Placopecten akihoensis (MA·
TSnloTo) etc, other pelecypods. gastropods. corals, echinoids, brachivpods, balanids. bryozoan-fragments and shark's
teeth. The Moniwa fauna indicates awarm water condition. The specimensof cosibensis ha11zawae from the early
Miocene Sugota formation may be alittle younger than the Moniwa formation were found at Ukibuta, HigashiYuri-mura, Yuri-gun, Akita Prefecture,associated with such as Chlamys akitana(YoiwLnL\), Ch!amys cf. ingeniosa (YoKOY.-\:O.IA), P!acoPecteu akilwensis (lVlATsu:-IOTo), Patinopecten yamasakii itcasakiensis(Nom:RA), and Palinopecten l~imurai ugoensis (IlAT:\1 and NtstYA:-1!\), other molluscs. brachiopods, echinoids, balanids,
foraminifers and bryozoans. The Sugota formation indicates a warm thermal
condition. A few specimens from lateearly rviiocene formations as Otsutsumi,
Tsunaki. Utsuno, Ginzan and their correlatives were found. associated withsuch as Chlamys miyatokoensis \ Noi\IIJRA
and lh TAl), Clzlamys kaneharai CYoKoY A:-IA ), Chlamys (Szciftopecten l stciftii (BER:"A RDI l, Clzlamys cosibensis 's. s\, Patinopectenparap/ebejus (.1'\o:-.n.:RA and 1-hTAr), andi11iyagipecte1l matsumorienesis :YlAsi;o.\and other fossils. This fauna mainlycomprises warm water animals. The
late ?\Iiocene Suenomatsuyama formation yielded specimens at Anaushi, Fukuoka-machi, Ninohe-gun. lwate Prefecture. associated with such as Ch!amys(Su;iftopecten) szciftii, Chlamys cosibensis(s. s. 1, Chlamys cosibensis lurpicula. Pali1lopecten kimurai \ Ym;oYA:O.L\1, Patinopecten

Koichiro MASUDA.
yamasal?ii ninohensis l\'L~sur>A and otherpelecypods. gastropods, echinoids balanids and bryozoans. This fauna is characterized by cold water assemblage. It
may be noticed that the specimens referable to cosibensis lzanzmcae from the
Suenomatsuyama formation are usuallysomewhat larger in size and more convex than those of the early l\Iiocene,
and the radial ribs of the former are
more distinct. These facts may support
the view of No:-.n:RA and HAT.-\J (1935,
1936) who concluded that with regard
to Chlamys cosibeusis the older the geological age is, the smaller is the size ofshells.
The deposition of the early Miocene
formations as the Moniwa and Sugota
proceeded under the influence of warm
thermal conditions, while the Tsunaki,
Otsutsumi, lJtsuno, Ginzan seas and theircorrelatives were influenced bv rather
cool thermal conditions. and the late
Miocene Suenomatsuyama sea was influenced by cold water. Thus. C!tlamys
cosibensis hanzmme was originallv a\Varm water inhabitant in the earlyl\:1iocene time, but became adapted todiverse environmental conditions of thelate early Miocene. and by the influenceof rather cold water conditions in thelate i\•liocene it became extinct.
The specimens of cosibe:zsis (s. s.) fromthe i\ 1iocene formations are usually rather few and the size of the shell is somewhat smaller than those from the Pliocene formations, \Vhile in the Pliocene
they became abundant and the size ofshell larger than those of the Miocene.
Clz!amys cosibensis turpicula occurs
from the late Miocene Shigarami and
Suenomatsuyama formations but its
number is rather few. In the Pliocene
they become common and exhibit somewhat less distinct concentric constrictions.
Abundant specimens of cosibensis lzeterog/ypta were found from the Pliocene
Sawane, Shiraiwa. Daishaka. Hamada and
Setana formations.
The view of N'o:-.JURA and HATAI concerning the relation between the geological age and the size of shell is also
supported in the case of cosibensis (s. s.}.
cosibensis turpicula as we!! as in the caseof cosibensis lzanzawae. Their occurrence
and geological ranges are shown in Table 2 and the text-figure.
1

Table 2. OL'currcnce of Chlamys cosibeusis group
Geological age

Early Miocene

I
I
I-,,,Formation name

-,

Late
Mio_

Pliocene

E

',

;...,

::>

"' E
3 =I ~ .:.:"' .:.: E
=
c e
2
r;:
0
gl
"'
0
~
"' ::l =:r.0 :::"' ~ "' -="' g::l"' == :n ="' 0"' =
c .g
:::>
:.c:
'-'
r::
"'
~
"'
(--<
a"'
"' :5. 0 < z"'
U5 ::.::
Subspecilic name '"'-._ 2 '"' Jl z
E .J

"'~

.:.:

::j)

'-'

cosibensis
hanzawae
lurpiculaheterog/ypla

::::>

0

= §

<;!

~

<;!

<;!

<l)

.:.:

::,

~

::j)

c;S

r·O

+ + +
+ + + + + + +

[f)

[f)

----

[f)

[f)

[f)

---

-

I

+ +I + + + + + + +
+
+
+ +
+ +
+ + +
+ +
I

MAS UDA : Miocene Pectinidae

MAsuoA photo.

Plate 13

36 8.

llfiocene Pectinidae from tlze Environs of Sendai

Illtoecntl
Early

I La

I

to

Pl1JCC!'O

r- - - , - - - - - - A'- ......-------- B----.,~--~c' '----.> D

Text-fig.
Showing the geological ranges and thelines of evolution of Ch/amys cosibensis group.
:\- Chlamys cosibensis lumzmcae
1\L\Sl"DA

B-Chlann·s cosibensis cosibensis(Yo~-;(n-A.\IA)

C-Citlamys cosibensis turpiwla('YOKOYAMA)

D-Ch/amys cosibe11sis heteroglypta(\"OIWYA~IA)

From the above it is thought that
cosibensis (s. s.) branched off from cosibeusis lwuzawae in the late early Miocene,
and reached its maximum flourishing in
the Pliocene where it became extinct.
It is inferred that cosibensis turpicttlabranched off from cosibensis (s. s.), andcosibensis heterog!yp!a from cosibensis
turpicula, and that they represent parallel forms of slight subspecific distinction. The Californian Chlamys zcattsi.
Chamys zcattsi morani, Chlamys nutteri
and Chlamys etclzegoini are considered to
be species closely related to the Japanese ones, hut with regard to their interspecific relationship future study may

Explanation of Plate 13(Natural size)
Figs. 1-!l. Cltlamys cosibensis (YoT<OLU·IA)
l. l~ight valve. SM. Reg. No. 6161. Loc. Right stream cliff. northwest of Daishaka. Nami·
oka-machi. Minami-Tsugaru-gun. Aomori Prefecture. Daishaka formation.
2. Left valve. DGS. Reg. No. 3685. Loc. Same as above.
:~. Right valve. Topotype, IGPS. coli. cat. no. 13315. Loc. Koshiba. Yokohama City, Kanagawa Prefecture. Koshiba formation.
4. Right valve. DGS. Reg. No. 3686. Loc. River cliff of the Chikagawa stream. about 200
m. from the sea shore at Chikagawa. Tanabu-machi. Shimokita-gun. Aomori Prefecture.
Hamada formation.
5. Right valve. IGPS. coli. cat. no. 72556. Loc. Same as above.
6a, b. a, Hight valve. b. Interior view. DGS, Reg. Xo. 368<. Loc. Same as abo\·e.
7. Right valve. DGS, Reg. No. 3686. Loc. Same as above.
8, !l. Left val\·e. DGS. Reg. No. 3686. Loc. Same as above.
Figs. 10-15. Ch/amys cosibensis hanzau·ae MASVDA. n. subsp.
lOa. b. a, Right valve. b. Interior view. Holotype. DGS, Reg. No. 3690. Loc. Ukibuta. Hi·
gas hi· Yuri-mura, Yuri-gun. Akita Prefecture. Sugota formation.
11. Right valve. DGS. Reg. No. 2691. Loc. Same as above.
12-1·1. Left nlve. DGS. Reg. Xo. 3691. Loc. Same as abo\·e.
15. Right valve. IGPS, coli. cat. no. 16084. Loc. Kita-Akaishi, Sendai City, Miyagi Prefec·
ture. l\loniwa formation.
Figs. 16a. b. Chfamys cosibensis lurpicufa (YOKOYA~IA)a, Right valve. b. Left valve. Topotype. DGS, Reg. No. 3698. Loc. Left river cliff of theSusobana-gawa at Shimoniregi, Shigaremi-mura, Kami-1\tinochi·gun, Nagano Prefecture.
Shigarami formation.
Figs. 17. 18. Chfamys cosibensis heteroglypta (Yoti:OYA~tA)
17a-c. a, Right valve. b. Left valve. c, Hinge area. DGS, Reg. No. 3687. Loc. Same as
Fig. ·1.
18a, b. a, l~ight valve. b. Hinge area. DGS, Reg. !\o. 3688. Loc. Same as Fig. 1.

Koiclziro AfASVDA

1:3:2
settle. the problem.

References
R. (1906), The Tertiary and Qua·
ternary Pectens of California. Prof. Pa·
per, U.S. Geol. Sun• .. No. 47. pp. 7-146, 53
pis.
DALL. \V. H. (1907). Descriptions of Xew Species of Shells. chiefly Buccinidae, fromthe Dredgings of the U.S. S. "Albatross"during 1906. in the Xorthwestern Pacific,
Bering, Okhotsk and Japanese Sea. Smith.
.\lise. Col/., Vol. 50, Pt. 2, pp. 139-173.
HA:"ZAWA, S. (1950). Tertiary Paleogeogra·
phy of North Japan. Short Papars. IGPS.
No. 2. pp. 7·1·98.
IlATAI, K. (1936), A Note on the Distributionof Certain Species of 1\farine Inverte·
brates. Bull. Biogeogr. Soc. japan. Vol. 6.
No. 12, pp. 123-Hl.
- - and S. NISI\'A:\IA (1939). Palaeontological Notes on Certain Japanese Scallops.
]our. Geo/. Soc. japan, Vol. 46. 1\lo. 544,
pp. 37-•IG, 2 text-figs.
KuBOTA, K. (1950). Explanation of Cenozoic
Fossils from Northern Japan, 9, Fossil
Pectinidac from the Sctana Series. Ceuo·
zoic Research, No. 6. pp. 12-18. 2 pis.
Kt:RODA, T. (1929-1935), An Illustrated Cata·
Iogue of the Japanese Shells. Pts. 1-16,
l'e1mS, Vol. 1-5, Append., pp. 1-154.
- - (1931), Fossil Mollusca in F. Ho:--:1\IA.
Shinano Chubu Chishitsu·shi (Geology ofCentral Shirwno), Pt. 4, pp. 1-90. 13 pis.
1\L.,Sl'DA, K. (195~). On the :\Iiocene Pecti·
AR:"OLD.

nidae from the Environs of Sendai: Part
14, On Pecten swiflii BEI~:'\MWI. Tmns.
Proc. Palaeout. Soc. ]apau, .1\'S. JVo. 34,
pp. 89-96. pl. 9.
NOl\ILA:->D, J. 0. (1917), The Etchcgoin Plio·cene of !\fiddle California. (}niv. Calif.
Pub/. Geol., Vol. 10, pp. 191-240. 7 pis.
NoMt:RA, S. and K. IIATAI (1935). Pliocene:1\·Iollusca from the Daisyaka Shell Bed
in the Vicinity of Daisyaka, Aomori·ken.
Northeast Honsyu, Japan. Saito lfo·olz KaiMus., Res. Bull., No. 6. pp. 83-137, 5 pis.
- - and - - (1937). A List of the I\liocene
Mollusca and Brachiopoda collected fromthe Region lying North of the Nanakita
River, in the Vicinity of Sendai. Rikuzen
Province, Japan.Ibid., No. 13, pp. 121-145,
5 pis.
YoKOYA:>.IA, M. (1911). Pectens from the Koshiba Neogene. jour. Geol. Soc. Tokyo, Vol.
18. No. 208. pp. 1-5. 1 pl.
- - (1920), Fossils from the l\liura Peninsula
and its Immediate North. four. Col/. Sci.,
Imp. Univ. Tohyo, Vol. 39 . .-lrl. 6. pp. 1193, 20 pis.
- - (1923), On Some Fossil Shells from theIsland of SaishO in the Strait of Tsu·shima. Ibid .. Vol. ·14, Art .. 1. pp. 1-Y. 1 pl.
- - (1925). Tertiary Mollusca from Shinanoand Echigo. jour. Fac. ,C,'ci., Imp. Uni1•.
Tokyo, Vol. 1, Pt. I. pp. 1-23. 7 pis.
- - (1925), Mollusca from the Tertiary Ba·
sin of Chichibu. Ibid.. Vol. 1. Pt. 3, pp.
111-126. 2 pis.
- - (1926), Fossil Shells from Sado. Ibid.,
Vol. I. Pt. 8. pp. 249-312. 6 pis.

Trans. Proc. Palaeont. Soc. Japan, N. S .. 1\o. 35, pp. 133-137. pl. J.f, Sept. 15. 1959.

:JG7.

SOME PELECYPODS FR0:\1 THE TSUKI.\'OURA FORMATIONIX MIYAGI PREFECTURE*(Studies on the Dogger Pelecypods in Japan. 2)
ITARU IIAYAr.U
Geological Institute. Uniyersity of Tokyo

J'l J itli~i~ I'"'~ :li-ff..@f!i~f'l!:4±lf!i~llMi'tl$0tHIIJ~~~¥c -t:"0tll~cc:~t±IT.O J'l J

iliili'y~f!j(;:I;J:-·.&oY~l,.l'-ftEf!i~:[g~ i;d1. .0~;.

C0.t$1®d: IJ Chlamys. Ctenostreon 0)

Wffll! t -ld~ilf(O) Loplw 2 fill 'i> ~~Jj Ld: O)"t'i\cll.'I!T 7.. <

j~

7.k

.f'&

The Tsukinoura format;on, mainlycomposed of coarse sandstones and con·glomerates. is distributed at the eastern
half of Kodaijima island and southerncoast of Tsukinoura in the neck ofOjika peninsula, l\liyagi Prefecture. It
bears several fossil beds on the coasts
along the Kodaijima channel. two of
which are most striking. The lower
bed is composed of bituminous sandstone and shale, containing shell-banksof Bakevellia sp. and Eomiodrm vulgaris
HAYAMI (1958). The latter species has
been known from similar facies of theLias of this country. Its range is now
known to extend into the lower Dogger.
The upper bed is a ferruginous granularconglomerate. Because of the coarsegrained matrix. the detail of fossils andminute specimens can be hardly observed, but the following species withrelatively large size are distinguishable
in my collection.

Because of the absence of any guidefossils. the age of this formation cannot
be determined. but it is presumed to be
Bajocian or slightly later, for the underlying Kodaijima formation can be cor·
related to the Aratozaki formation of
Shizukawa area by the common occur·
renee of Trigonia sumiyagura KoBAYASHI
and KASE:"O. 1947 (KoB.\YASHI and rvioRI.
1954) and some other pelecypods. Someauthors correlated the Tsukinoura to
the Aratozaki formation, but I could
find no common species between thetwo faunas.
I express my sincere thanks to Prof.
Teiichi KoaAY.\SHI of the Uni\•ersity ofTokyo for his kind guidance and supervision of this manuscript.

Ch!amys kobayashii H.-\ YA~Il. new species
Ctenostreon ojikense HAYAMI. new species
Lopha a sp. indet.
Loplw b sp. indet.

Genus Clilamys Rooi:-;c. 1798

* Received Sept. 19. 1958:

Description of Species

Family Pectinidae LAMARC((

Chlamys kobayashii HAYA~Il. new species
Plate 14, Figures 1-2.

Description :-Shell medium to large
for genus, inequivalve, subequilateralread Dec. 7.

1958.

1:33

ltaru, H4LU!I

1:3-1

exclusive of auricles. nearly acline, notstrongly inflated. much higher thanlong: antero-dorsal margin of main bodyslightly sinuated, more or less gaped.
while postero-clorsal margin of main
body is slightly convex. passing gradually into venter: auricles of Clz!amys-type,well defined. very unequal : byssal
auricle linguiform, supported by anauricular sulcus, excavated below by aprofound byssal notch: posterior auricleof each valve truncated subrectangularly, cancellate with about 10 radial
riblets and numerous concentric lines:

left anterior one also netted, but its
posterior margin fairly concave in lower
half: surface ornamented with 36-.JO
radial ribs. some of which are bifurcatedtowards ventral periphery in rightvalve and insert secondaries in left
valve: radials angular. roof-shaped intransverse section; intervals nearly as
wide as ribs. marked with numerous
concentric fila: ctenolium probably
present: umbo slightly prosogyrous.
submesial; apical angle about 75 degrees
or slightly larger.

:l1eusur(!ment i11 mm.

LengthHeightHolotype (!\Il\1 3124) right ex. mould
Paratype (:.1M 3125) right ex. mould-11.5

4-l.li+

62.0
46.5+

Obsen,ation and comparison :-Seven
specimens "·ere procured. The halotype (Fig. 1). though fairly compressed
antero-posteriorly. shows the nearlycomplete outline. byssal area and radial
ornamentation on the main body andboth auricles. The radial ribs increase
their number by bifurcation in rightvah·e and by insertion in left valve.
The mode is commonly seen in normal
species of Chlamys. This is some\vhat
similar to Cfllamys mojsisovicsi KorHYASHI and IciHKAW,\ (1949: NAKAZAWA,
1952: lciHIC-\W,\, 1954) from the Carnic
and C. kurumensis KoBAYASHI and l-L\YA:\11 (lL>.Y.\~11. 1D57) from the Lias of thiscountry. But it is distinguishable fromthe two in the large dimensions, more
prominent concentric markings andstronger and less flat-topped radial ribs.
Radial riblets on posterior auricles are
more in number than in mojsisovicsi andlwrumensis. As to foreign species,
Ch!amys textorius ScHLOTHEnl (GoLDFt:ss,
18311: Du~toRTrER. 1867; DEcHASEAllX,
1936. etc.) from the Lias and C. ambigua

Thickness
7.0(MCNSTER) (Goi.DFt:ss, 1836; GREPPI:"i,1899: DEciiASEAliX, 1936: Cox, 1952. etc.)from the Dogger are two allied species
to this. In the number of radials on
main body this is intermediate between
the two species. which are consideredby STAESCHE (1926) and DECHASEAux(1936) to have been connected phylogenetically. But further close comparison
proves that this is distinct from themin the more roof-shaped less scaly
radials. and smaller apical angle. In
the radial ribbing and their number.
this may be closer to Clzlamys subtextoria(l'vic:-~sTER) (GoLDrcss, 1836: STAESCHE,
192G; DECIIASEAux. 1936: Cox, 1952. etc.)from the Callovian and later of Europe
and India, but the shell is larger andposterior auricle more vertically truncated at the postero-dorsal corner thanthat species.
Occurrence :-Common at the Kodaijima strait. A left valve collected by
KonAYASIIJ and F\·KADA from the upper
part of the Kosaba sandstone formation
at Shibitachi of Karakuwa area. northern

367.

Pelecypods from the Tsukinoura Formation

11iyagi Pref. This species is presumed
to be a characteristic element of the
Tsukinoura and upper Kosaba faunules
which are slightly younger than the
Trigonia sumiyagura-faunules in thelower Aratozaki. lower Kosaba and Kodaijima formation.
Family Limidae D'ORmGxY
Genus Ctenostreon o'EJCHWALD, 1862
Ctenostreon ojikense IIA Y.HJJ,
ne\v species
Plate 14. Figures 3a-b.

Description :-Shell large for lim ids.
cquiyaJve, incquilateral. inflated, somewhat irregular in outline but usuallysubovate, fairly inequilateral with aslightly opisthocline main body and,\Jeasurement i11 mm.
Holotype (:..IM 31:!6) left in. and ex. moulds
Paratype (l'l'l:\1 3127) left internal mould

Observation and comparison :-Represented by five specimens. The~· aresome,,·hat variable in outline. but allshow similarly strong convexity andregular number of radials. The holotype specimen (Figs. 3a-b) may beslightly compressed in dorso-ventral
direction hut its outline is nearly complete. Judging from the radial ribbing
and ligament structure, this is a limid
and referable to Ctenoslreon. The radialplications are 7 or 8 in this species andit is small in comparison with most
species of the genus. The concentriclamellae are much weaker than normal
Cteuos/reoll. In the mode of ornamentation only Ctenostreon paucicostatum
LEA:":Z.>. (19-!2) from the Lias of Neuquen
resembles this but the shell is probably

unequal auricles. neariy as long as high;test moderate in thickness: antero-dorsal
margin of main body long, straight~
postero-dorsal short. slightly convex:
dorsal margin roof-shaped in externalview, but hinge-line straight; anteriorauricle well defined. inflated to form awidely gaped anterior margin: posteriorauricle large, ill defined from main body,more or less obtusely truncated: surface ornamented with 7 or 8 stout, roofshaped radial p!ications which bear
several tubercles: concentric lamellae
considerably weak for genus but fairly
prominent on anterior auricle: umboslightly prosogyrous. submesially placed.
not rising above dorsal margin: ligament area not very wide, provided witha large. slightly prosocli nc. triangularligament pit below beak: apical angle
exclusive of auricles about 105 degrees.
LengthHeightThickness

65.0
53. 5+

60. 0
60.2

11. (I
12.0

much taller and thicker with a broader
ligament area and the apical angle smaller than this species. This is obviousl~r
different from Ctenostreon sp. from the
Aratozaki formation of Shizukawa area(l-lAYAl\11, 1959, ?viS) in the more roofshaped radials of smaller number.
OccwTe11re :-Common at the Kodaijima strait.
Family Ostreidae L.>.~JARCK
Genus Lopha BoLTE!':. 1798(=Aiectryouia FISCHER DE WALDHE!:-1. 1807)

Lop/w a sp. inclet.
Plate 14. Figure 4.

Represented by a solitary right ex-

186

Itaru H.4.YAMI

ternal mould (i\L'vl 3128, 19.0 mm. long;
36.0 mm. high). Shell small. subequilac
teral, ovate, not strongly inflated, bearing nine radial angular plications which
are very irregularly spaced, increase
their number mainly by irregular insertion and probably interlock at valvemargin with those of counter valve;
median parting not strong; concentric
laminae prominent. This may belong
to the group of Lopha marshii CSowERBY)(1814; Cox. 1952) from the Aalenian toKimmeridgian of Europe and India. but
the dimensions are much smaller andthe outline more ovate than that species.
Occurrence :-Rare at the Kodaijima

Another right valve represented byinternal and external moulds (MM 3129,
22.0 mm. long ; 55.5 mm. high) disagrees
with the preceding form in the morevertically elongated outline, absence ofmedian parting and more delicate plications which are restricted near ventral
periphery.
Occurrence :-Rare at the Kodaijima
strait.

-------------------------------

strait.

Loplza b sp. indet.
Plate 14. Figure 5.

Explanation of Plate H
Figs. 1-5.

Pelecypods from the Tsukinoura Formation at Kodaijima strait, south of Tsukinoura. Ishinomaki City. i\Iiyagi Pref.
Clz!amys kobayashii HAY,\:\11, new species ................................................ p. 133
Fig. 1. Gypsum cast of right external mould. holotype (M:\I 3124), x 1.
Fig. 2a. Right internal mould. paratype (MM 3125). xl.
Fig. 2b. Clay cast of the same specimen, x L
Ctenostreou ojikense HAYA:\11, new species .............................................. p. 135
Fig. 3a. Left internal mould, holotype (;viM 3126), X 1.
Fig. 3b. Gypsum cast of the same specimen, x 1.
Lopha a sp ............................................................................... p. 135
Fig. 4. Right external mould (MM 3128), X l.
Lopha b sp ............................................................................... p. 136
Fig. 5. Right external mould (Mi\1 3129). x l.
Figs. 6-13.

Pelecypods from the upper Aratozaki Formation at the east of Shizuhama.
Shizukawa·machi. Miyagi Pref.
. ................ p. 139
Ko/Jayashites hemicytindricus HA YA:'-11. new species ............ .
Fig. 6a. Left internal mould. holotype (1\!M 3130). x2.
Fig. 6b. Clay cast of the external mould of the same specimen. x2.
Fig. 7. Right internal mould, paratype (MM 3131). x2.
Fig. 8. Left internal mould (Ml\1 3132), x2.
Fig. 9. Clay cast of left external mould (l\IlVl 3133), x2.
Fig. 10. Left internal mouid (!VIM 313~). x2.
Protocardia inaii IIAYA:\11. new species .................................................. p. 140
Fig. 11. Clay cast of right external mould. holotypc (Ml'vl 3135), xl.
Fig. 12. Right internal mould. paratype (MM 3136), x2.
Fig. 13. Clay cast of left external mould, para type (l\1M 3137), X 2.
All specimens illustrated here arc kept in the Geological Institute, University of Tokyq.

HA Y AMI:

Dogger Pelecypods

411

Plate 14

367.

Pelecypods from the Tsukinoura Formation

References
Cox. L. R. (1952). The Jurassic Lamellibranch Fauna of Cutch. Pal. Indica, Ser.
9, Vol. 3. Pt. 4.
DECHASI>Acx, C. (1936). Pectin ides jurassi·
ques de !'Est du Bassi'n de Paris . . inn.
Palcont., Tom. 25.
DDJ<>RTIER. E. (1867). Etudes paleontologi·
que sur les Depot jurassiqucs de Bassin
du Rhone. Vol. :.!. Lias inferieur. Paris.
GOLDFCSS, A. (1833-1840). Petrefacta Gcrmaniac. Bd. 2. Diisseldorf.
GREPPI:-1, E. (1899), Description des Fossiles
du Bajocien superieur des Environs deBale. Mbn. Soc. Pal. Suisse. lfo/. 26.
HAYA:\11, I. (1957). Liassic Chlamys, "Camptonectes" and other Pectin ids from theKuruma Group in Central Japan. Trans.
Proc. Pal. Soc. japan. N. S .. "Vo. 28.
- - (1958), A Review on the so-called Liassic "Cyrenoids" in Japan. ]apa11. jour.

Geogr .. Vol. 29, Nos. 1-3.
- - (1959. l\IS). Bajocian Pelecypods of the
Aratozaki Formation in Northeast Japan.
Ibid., Vol. 30. (in press)
KonAY.\SHI. T. and IcJm.:AwA, K. (1949).
Tosapecten gen. nov. and oth~r upper
Triassic Pectinidae from the Sakawa
Basin in Shikoku, Japan. Ibid .. Vol. 21,
Nos. 1-4.
- - and 1\ioRr. K. (1954). Studie!' on theJurassic Trigonians in Japan, Part 2.
Prosogyrot rigonia and the Trigoniinae.
Ibid .. Vol. 25. Nos. 3-·1.
LEA!"ZA, A. F. (19-12). Los Pelecipodos delLias de Piedra Pintada en ei Neuqu~n.
Re~·. !1luseo La Plata, N. S.. Tom. 2, Pal.,
No. 10.
SO\I'ERBY, J. (181-!). ~Iineral Conchology ofGreat Britain. Vol. 2. London.
STAESCIIE. K. (1926). Die Pectiniden desschwabischcn Jura. Geol. Pat. Abllandl.,l'ol.S .. Ed. 15.

Trans. Proc. Palaeont. Soc. Japan. N. S.. No, 35. pp. 138-141. pl. 1:1. Sept. 15. 1959.

:.3!18.

SOI\lE PELECYPODS FROl\T THE UPPER ARATOZAKI FORMATIONINCLUDING A NEW GENUS KOBA.YA.SHITES*(Studies on the Dogger Pelecypods in Japan. :j)
ITARU I-IAYAIVii
Geological Institute. University of Tol~yo)itJJf~iJ:i'ffilfll~ t.: ·:; :'i -ffJE~f{f,!\: ~r~llliti!1J0Jffal:t•il5l:$~:±~tE!J:fit~:1J:,

fmilli-fi!J.I<i~JI\l0WJW.;.:.

Jsognomon. Protocardia 0(tl!l::!f.JJ'U..: gen·illiid -i>1H.:~fHTll(?'(~@!J:;;_,;:,,CO) gen·illiid :;t::;.;!.7-8~il<30 Gerl'illia c==:!l~Hc0 Hoernesia r::~-\~(J:l"CP
7.. !J:, ~'-:itt ~ IIJ]~r::~ 7.. 0)~ J\obayashites (tfrfill) c !.- "Liftl~"t;:,c0

As noted before (HA YA!\II. 1959). theupper part of the Aratozaki formationin Shizukawa area is composed of conglomerates and ferruginous coarse sandstones. Fossils arc very rare, but athin layer of pelecypod-bearing black
bituminous sandstone is exposed on the
shore between Hosoura and Shizuhama.
The following species collected therefrom are described in this paper.

m* m

the bed in the Arato formation. Diverge opinions were expressed on therelationship of the formation ·with theunderlying Aratozaki by several otherauthors. So far as I can see in thisarea. however. the two forma! ions arealways in contact with each other withstrike faults. and it is indecisive directlyfrom field observation whether the relation is disconformablc or conformable.
The fossil bed in quest ion is located near
the fault zone. but seemingly lies conformably on the conglomeratic sandstoneof the Aratozaki formation. As similar
bituminous beds are occasionally inserted in the upper part of the formation
at some other localities. I am inclined
to consider that such beds imply temporal lagoonal conditions in the upper
Aratozaki stage. The age is presumed
to be somewhere in Bajocian.

Kobayasl1ites hemicy/indriot.~ H..-. YA!\11. new
genus and new species
Jsog110IIIOII sp. ex gr. l'ikuzenicus (YC•KOY,\liiA)

Pro/acardia inaii HA \' A~l 1. new specie~

The first species is undoubtedly agervilliid but the shell is unusallyinequivalve and the hinge-line \'ery longfor Gen•il!ia (s. s.) and Cultriopsis. On
this account I propose a new genericname. 1\obayashites. for it. The lastspecies seem more or less intimate tosome \Vestern Dogger forms.
Previously J:-.;,,1 (1939) reported .. Perna
sp. ··from this locality and included the

Description of speeies

Family Balmvelliidae K10\c, 1850.
em. Cox, Hlri:l* Received Sept 19. 1958: read Dec. 7. 1958

Genus Kobayashites 1-IAYAllll, new genus
1:38

368.

Pelecypods from the Upper Aratozal~i Formation

Type species:- Kobrryashiles lzemicyliudricus IL-\ YA~rl. new species, Bajocian.

Northeast Japan.
Diagnosis :-Shell small for family.
elongated posteriorly, soleniform, very
inequiva\ve, neither strongly curved,
nor alate; left valve hemicy!indrical.
provided with a wide byssal gape anda septum-like thickening below umbo,
but right valve nearly 11at; hinge-line
unusually long: posterior margin short :subterminal: hinge and iigament structures of Bakel'ellia-type.
Remarl?s :-This genus is characterized by the hemicylindrical inequivalve
shell and unusual length of hinge-line.
It may be an offshoot from Gervillia
judging from similarly wide gape. subterminal umbo and elongated outline.

139

But Jurasso-Cretaceous Gerril/ia DEFR:\:-<cE (1820), Jurassic Cultriopsis Coss~1A:-:N(1904) and Triassic A.ugustel/u \VA.-\GE:-<(1907) have equivalve or subequivalve
shell, more or less alate posteriorly andstrongly curved with much shorter
hinge-line. Jn these respects this is
somewhat similar to Hoemesirr L... caE(186S) chiefly from the Triassic of Europe. Such a septum-like thickening
helow umbo is a!so seen in Hoemesia
jommis austriae KLIPSTEr:-:. type of thatgenus (BITTNER, 1895). But if comparedwith the type form and /!. socialies
Scttl.OTIIEI7vl, the shell of the Aratozaki
form is less inequivalve. less contorted
and much more elongated horizontally.
:Moreover. such a wide hyssal gape isprobably unknown in I!oernesia.

,-·
:

I

'

'

\,

Text·fig. 1.

..

.......... __ _Interior of Kobayashites lzemicyliiU/ricus HAY.-\\11, n. sp. (restored)

Koba)'(tslzites lzemicyli ndricus IL\ Y A ~11.

new species
Plate H. Figures 6-10 and Text-fig.

DescriPtion :-Shell small for gervilliids. highly inequivalve, slender. nearlystraight, solenifonn in outline, morethan 3. 5 times as long as high: test
thin; hinge-line very long. occupying
most of shell-length; posterior margin
short: ventral margin straight. subparallel to hinge: umbo subterminal, moreor less prosogyrous: both wings undeveloped. not discriminated from main
body: left valve moderately inllatedwith protruded umbonal area above
hir:ge. but right valve much flatterwith scarcely salient umbo. slightly

contorted in anterior area: byssal gapewide, occupying most of anterior marginof left valve, crescentic in anterior
but indiscernible in right va!ve: ligament area narrow. faintly striated horizontally, provided with four or more
small. subequidistant. subquadrate ligament pits: their interspaces about 3-4
times as long as pits: ligament area
subparallel to valve-margin in left valve
but very oblique in right; cardinal teeth
one or two in each valve. slightly oblique, directed to the anterior end of
hinge-margin: hinge-plate supported bya septum-like thickening helm\· umbo;
laterna! tooth on each valve weak butvery long. running parallel and very
close to dorsal margin: su:·face smooth
but for fine concentric growth-lines.

140

Itant H4. YAM!
Jftwsm·ement in mm.

LengthHeightThickness------

Holotype (l\i!\·1 3130) left in. mould
Paratype (MM 3131) right in. mould
Paratype (l\IM 3132) left ex. mould_ Observation and comparison :-Four leftinternal moulds. though not complete,sho"' characteristic internal features.
long hinge-line and wide byssal gape.
The right valve is represented only
by one internal mould (Fig. 7), but theinequivalveness is obvious. Its generaloutline is known in a left externalmould (Fig. 9). The outline and inequiv~lveness are quite different from thoseof hitherto described species of Gervil!ia
and allied genera. I could find no com·parable species with this in foreign
literature.
Occurrence :-Procured on the coast
east of Shizuhama in Shizukawa-machi,
Miyagi Prefecture (Provi nee of Rikuzen).

Family Isognomonidae DAu.
Genus Isoguomo11 SoL:\l"DER. 1786
Istignomon sp. ex gr. rikuzeuicus(YOI\OYA~IA)

Several internal moulds of a large
isognomonid are at hand. As to theligament and byssal structures I could
find no diagnostic character to distinguish it from I sognomon rikuzenicus (Yo-

30. 5+
15. 0+
300

8.5

6.5
8. 0

4.0
1.5
3.5

KOYAMA) (1904), (HAYAMI, 1957) from theLias of this area.
Occurrence :-The same as the preceding.

Family Cardiidae LAMARCKGenus Protocardia BEYRICH. 1845
( =Protocardium, auct.)
PnJtocardia inaii HAYAW, new species
Plate J.t Figures 11-13

Description :·-Shell medium, equivalve.
subequilateral, rouncl. strongly inflated,
more or less longer than high, noncarinated: umbo slightly prosogyrous.
rising above hinge, submesial: lunuleand esct;tcheon not impressed; posterior
radial ribs about 22 in number, regularin strength, distributed in about afourth of whole surface from posterior
end: remaining part marked withnumerous faint radial threads: concentric ribs absent; growth-lamellae somewhat irregular in strength and interval;
musculature weakly impressed: rightvalve having a conical cardinal 3b andsmall 3a. deep subvertical socket 2' anda pair of remote lateral teeth.

11/easurement in 111111.

LengthHeightThickness

Holotype (MM 3135) right ex. mould
Paratype (1-IlVI 3136) right in. mould
Paratype (MM 3137) left ex. mould

28.5
14.5
10.5

24.0

7.5
4.0
4.5

~----

------

11.5
9. 0

J68. PelecyPods from, tlw Upjx;r Aratozaki Formation
Observation and comparison :-Represented by four specimens. The posterior radial ornaments of Protocardia areseen in the holotype and other externalmoulds. The holotype shows numerous
faint radial threads on its main surface,but is more or less compressed inantero-ventral to postero·clorsal direction. The original outline is presumed
to he more globose and better represented by other illustrated specimens.
This may be an ally to Protocardia
buckmaui (MoRRIS and LvcETT, 1853)(=Cardium cmzsobrium TERQUEM and]ot.:RDY,1871) from the Inferior andGreat Oolite, but the umbo is not sosalient above hinge as that species. In
this respect this is more similar to Protocardia sp. in BENECKE (1905, p. 231, pl.
17, figs. 7-8), but the generat.outline ismore round and equilateral.
Occurreuce :- The same as the preceding.

References

141

zialk. Bs.·Lothr., N F., !left 6.

BITTl'\ER, A. (1895), Lamellibranchiaten dcr
Alpinen Trias. Abh. k. k. geo/. Reiclzsanst.,
Bd. 18. Heft 1.

CosSMAN:-1, M. (1904). Note sur I'Infraliasde Ia Vendee et des Deux-Scvres (Suite).
II, Pelecypodes. Bull. Soc. geot. France,
Ser. 4, Tom. 3.

Cox, L. R. (1954), Taxonomic .1\otes on I so·
gnomonidae and Bakevelliidae. Proc. Ma·
lac. Soc. Lo11d011, Vol. 31, Pt. 2.
I. (1957), Liassic Gerz•illia and !so·gnomon in japan. japan. jour. Geol.
Geogr., Vol. 28. b'os. 1-3.

HAYAl\li,- - (1959, MS).

Bajocian Pelecypods of the
Aratozaki formation in Northeast Japan.
Ibid., Vol. 30. (in press)
IN.\I, Y, (1939), Geology of the Environsof Shizugawa-mati, Miyagi Prefecture.
}our. Geol. Soc. japan, Vol. 47. No. 548.

MORRIS, J. and LYCETT, J. (1853), A Monograph of the Mollusca from the Great
Oolite, etc. Palaeontogr. Soc. Londo11.
TERQUE~I, M. 0. and joURDY, E. (1871),
Monographic de J•thage Bathonien dansle Department de Ia Moselle. Mim. Soc.
geol. Fra11ce, Ser. 2, Tom. 9.
WAAGEN, L. (1907), Die Lamellibranchiaten
der Pachycardientuffe der Seiser Aim.
Ablz. k. k. grot. Reiclzsanst., Bd. 18, Heft 2.

BENECKE, E. W. (1905), Die Versteinerungender Eisenerzformation von Deutsch·Loth·ringen und Luxemburg. AM. geol. Spe·YoKOYAMA, M. (1904), On some Jurassic
Fossils from Rikuzen. jour. Colt. Sci. Imp.
Univ. Tokyo, Vol. 18, .4rt. 6.

Trans. Proc. Palacont. Soc: hi>an, ·1-J. s., N'o: 35, p.'ui, Sept: .15, 1959

SHORT NOTES
5.

IDENTl TY OF ALGAL TUBIPIIYTES lVIASLOV. Hl5G. AND
HYDROZOAN GENUS NIGRIPORELLA RlGBY. 1958
KENJI KONISHI
Geological Institute, University of Tokyo

Permo-Pennsylvanian stratigraphersand paleontologists have observed apeculiar organism frequently in carbonate rocks, which sometimes is a verysignificant limestone-builder.
To the author's knowledge. NEwELL,RIGBY, FiscHER, WHITE1>1AN, HicKox and
BRAou:v (1953; e. g. pl. 17, fig. 3, pl. 18:
p. 112) are the first who illustrated
clearly the organism and called it as.. hydrocoralline (?) ·•. NE\HLL illustrated the same organism later (1955) again
as "hydrocoralline (?) ". The exactly
identical fossil has been found from I he
Lower and Upper Pern1ian rocks-(Zonc of
Parafusulina to Zone of Yabeina) in theJapanese Islands while the author has
sought for calcareous algae. .
.
Lately, M.\st.ow (1956, p. 82-84, 91, 20·1,
233, etc .. pl. 25, figs., 1-3, pl. 26, pl. 27.
figs. 1-3, text-fig. 22) described the organism from the Upper Carboniferous (C 3 )and Permian of the Ural Mountains* inthe belief of its possible Schizophycean
nature and named it Tubiplzytes, a monotypic genus based on T. obscurus n. sp.
RIGBY (1958) proposed a new genus
Nigriporella for the same fossil and reaffirmed its hydrozoan nature. According to him, the genus even ranges fromthe Lower Carboniferous (Mississippian)to Upi)er Perm ian, and consists of two
species, N. magna RIGBY (type species)
and N. mi11ima RIGBY.
The present author would have a

diJliculty in supporting its algal natureand its inclined to agree with the otheralternative, that is probably a hydrozoan.
From his recent studies. he would saythat Nigriporella is not uncommon in the
Permian rocks in such widely scatt~n;dareas as Mexico, Guatemala, the Carnic
Alps, Afghanistan, Burma, and South
China, besides the Japanese Islands andNorth America .

Text-figures 1. Nigriporella sp. Lower
Permian Nabeyama formation, Kurakakeyama, Kuzu. Tochigi Prefecture, Ilonshu.
Coli. Kl\.54051003. x25.

References Citedn. P., 1956, Fossi I Calcareous Algae
in U.S.S.R. (in Russian) Pub/. U.S.S.R.
.4cad. Sci., Inst. Geol. Soc., No. 160, 264 p.
NEW~LL, N.D., 1955, Depositional fabric in
Permian rect' limestone. f. Ceo/., v. 63, p.
301-309.
-.RIGBY, ]. K., FISCHER. A. G., WHITEMAN,
A.}., HJCI,OX, }. E., and BRADLEY, }. S.,
1953, The Permian Reef Complex of the
Guadalupe !Vlountains Hegion, Texas and
New Mexico. W. H. Freema11 & Co. 236 p.
RIGBY, l K., 1958, Two new Paleozoic hydrozoans. f. Paleont., v. 32, n. 3, p. 583-86.
NfASLOV.

* MASLOV (ibid., p. 91) indicates its occurrence in the Upper Devonian on the table.
However, this should be understood as amisprint.
142

Trans. Proc. Palaeont. Soc. Japan, N. S., 1\o. 35. pp. 143-146. pl. 15, Sept. 15, 1959:~h!l.

SPINOMARGINIFERA FOUND I~ JAPANESE PERl\IIAN
KOJI NAKAMURA
Department of Geology and Mineralogy, Hokkaido Uni,·ersity;,j;:fll· ) 1V(;J: I)~~* ;fl.t: Spinomargi11ijera: :lt:.tllUil!lltt!~J: I) ;m (.., t: Spiuonwrgiuifera 1/ltli:~T ~ =:-.fl~ l!G~ (.., t:" RiJ; SpiJWmargi11ijera kueichou·ensis HUA1'G t Sp.
llltallgi NAKA!\IURA n. sp. 1:.1:1 Q' ~ '-r:n. b mx0=---~~J: I) ;m-r 0 '/):, ~~l!tit)!EJliH'i•O)mutation t \.1!.11« *;fl."(~' t: o 1... iJ· l...-"7@1! II'fC~t.,;:~:;f.:ii>t*~H-!ilf~0*li*· mi ~01f:lYIIF.:',~'R.HIL.t:0"t'tl'L--?tfrf!HtT~~-r:.1:>-??oGenus Spinomarginifera was establishedby T. K. lkA:"G, 1932, S. kueichmcensis
Ht·A:-.:c as genotype. The genus is espet:ially characteristic in having shellwith distinct marginal ridge, a feature
which strongly reminds the writer ofthe genus Marginijera as well as Eomarginifera. The former is yet distinguishabe from the latter two, in possessing shell ornamented by different
sculpture. The shell of the former israther smooth except for ;veakly developing plicae and very sparsely distributed tubercles or pustules, while
the shells of the latter two genera
possess rather strong radial and concentric plicae. especially at the apicalregion. So far as the writer is now
concerned, no species being assignable
into the genus Spinomargini[era seemto have ever been reported outside
South China. But the presence of two
species which should be surely assigned
into the genus Spinomargini[era has been
known in the collections of brachiopods
made by the staff of the Departmentof Geology and Mineralogy, Hokkaido
University from the Permian of theKitakami l\lountains, N. E. Japan. Oneof them is conspecific with the genotypeof this genus, and the other may be* R<Cccivcd Nov. 5. 1958: read June 20. 1956.

If! #

~

:-:

new to science. The writer wishes here
to describe them briefly.
Before going into description, thewriter wishes to offer his cordial thanks
to Professor l'vlasao l\lt=-ATo for his kind
guidance
throughout
thisstudy.
Thanks are also due to 1\-lr. S. Ku~rA:-~ofor taking photographs, and to Messrs.
H. TAKEDA, T. lVIAEr<AwA and M. HARA·
DA, Hokkaido Gniv. who placed many
excellent specimens at the writer's
disposition for study.
Description of species

Genus Spinomargini[era 1-IuM.;G, 1932
Spinomargin(fera kueiclzozcensis lkA:-;G
Plate 15. Figures 1-·1.
1932. Spi11omarginijera kueich01censis HUA!'G:

Palaeonto/ogia Sinica. Ser. B. Vol. 9.
Fasc. 1. p. 56, pl. V, figs. 1-11.

Shell small to medium in size. Hingeline straight which is the greatest
width of the shell. Ventral valve moreor less strongly convex and shows rather
remarkable geniculation at a distanceof 13 mm. from the beak. Beak rather
large. prominent and very much inclined
to turn over the hinge-line. l\lediansinus very broad and shallow and begins

1-14

Koji NAK;lMURA

to appear clearly from the point ofgeniculation. Ears moderately broad
and flatly convex. Cardinal area neverobservable. Surface sculpture varies
with age. In general, the shell of theearly stages is ornamented by widely
spaced, fine spines which are disposedquincuncially. They generally becomeplump tubercles as the shell becomesolder, and finally, those tubercles become changed into more or less complete plicae. However, there is to befound such a specimen whose shell is
ornamented only by tubercles. insteadof plicae, although it may show themature stage from the viewpoint of size.
The visceral disk of the dm·sal valve
is half-moon in shape, highly concave
at apical region and then flattened until
its anterior extremity, where it isstrongly geniculated to form a straightand rather long trai I. The more its
gcn iculat ion approaches towards thehinge-line, the less the angle of geniculation becomes. Ears moderately broad
and rather convex. Median fold almost
absent, but in some specimens very
faint gibbosity can be perceived especially in the anterior part beyond the
geniculation. Surface sculpture consistsof numerous spine bases which are
irregularly scattered. They are especially coarse on the auricles. Further
there are indistinct, irregular. sinuous.
concentric markings which are hardly
observable in the trail. Besides. smalland shallow pits are faintly developed
over the entire surface of the shell.
Radial striae are absent at the visceraldisk. although rather coarse striae are
faintly traceable in the trail. Interiorof the dorsal valve can be observedin some well preserved specimens. At
first, the presence of a median septum
must be noted. It begins just below
the beak and occupies about three-fourths or t\vo-thirds of the visceralportion in length. Next, the internal
marginal ridges must be taken into
consideration; they characterize thepresent species.
HcA:>:c once said that marginal ridgesof this genus are made up of threeparts; a median diaphragm and twolateral ridges. The first named part issituated nearly at the point of geniculation; it projects inward being parallelto the visceral disk. ~amely the marginal ridge makes 90° to the trail. The
weak lateral ridges arc separated into
two segments by a median septum: theyextend to become parallel to the hingeline and stand perpendicular to thevisceral part. Thirdly. one pair of longand slender adductor muscle scars isobservable at both sides of the posterior
position of the median septum, while a
few erect internal spines are crowded
between the median septum and brachial ridges in the anterior portion of theshell.
Remarks:-The specimens now at handvery much resemble the holotype of
this species, except for the fact that
the Japanese specimens are a little moretransverse than the Chinese. According
to HL\~c. however, this species is veryvariable both in size and in shape.
Accordingly the Japanese specimens
may be identified with the latter. Thisis easily distinguishable from the allied
species by the presence of a mediansinus in the ventral valve.
In South China, this species is believed to be found only from the Loping
series in association with Lyllonia fauna.
Hor.: Lower Kanokura series. Col!.:
T. MAEKAwA. Reg. No.: 11554. 12368,
12441, 12585. Lor.: Kamiyasse. Niitsukimachi, Kesennuma city, 1\Iiyagi Pref.
Col!.: K. NAI-u.:-.JL.HA. Reg. No.: 12584,
12374. 12586. Lac.: Kamiyasse. Niitsuki-

369.

SPi1wmarginijera found in japanese Permianmachi. Kesennuma city, Miyagi Pref.
Col!.: H. TAIOmA, Ivl. HARAnA and K.
XAKA~Il:RA. Reg. No.: 1~440. 1~64~. 12374.
Loc.: Imo, Yahagi·machi, Rikuzentakada
city, Iwate Pref.
Spi11omarginijera huaugi N.-\I>A;\ILI{A, n. sp.
Plate 15, Figures 5-i.
1932. Spi11omar,;inijera kueiclzozcensis mut. a
Ht·A:-;G:l'alaeol!l. Sinica, ser. B, Vol.

9. Fasc. J, p. 60, pl. V, figs. 12-13.

Shell medium in size, usually subrectangular in outline except ears.
Hinge-line straight. nearly equal to thegreatest width. Visceral cavity comparatively thick. Ventral valve verystrongly convex but does not show any
gen icu lation.
The visceral part is. however, clearly
distinguished from the auricles which
are rather flat.
Auricle expansions
rather broad and convex. l'l'leclian sinus
narrow but rather de~p throughout its
length. The surf ace ornamentation of
the ventral valve cannot be observed indetai I. owing to the bad state of preservation. except for a few coarse spinebases irregularly and sparsely scattered.
Internal surface of the same valve isornamented by very fine longitudinal
striae. There is recognizable a pair ofadductor muscle scars of elongate form
at the apical region. Dorsal valve isstrongly geniculate at the anterior end.
from where the very long trail begins
to grow.
Visceral part is slightly
conca,·e. which may be the most importa!lt bio-character of this species.
Auricles rather broad. Surface sculpture is composed of irregular growthlines and shallow grooves instead of
the spine-bases of the opposite valve.
l\ledian fold constantly present. l'v1ore
or less well preserved specimens show

l.t5

the interior of the same valve. The
marginal ridge is composed of threeparts: two lateral ridges and diaphragm,
which connect with each other. Diaphragm is standing just on the pointof geniculation. The more sharply thediaphragm may be situated in thecentral portion. the Jess it may appear
towards the lateral portion. Cardinal
process, which is trifid at the top,
projects slightly above the hinge-line
and unites anteriorly \Vith a median
septum which is as !ow as the septumof Productus proper. One pair of adductor muscle scars are elongately trigonal in shape. measures about G.~ mm.
in length and 2.8 mm. in width. They
are situated near by on both sides of
median septum. Besides, a pair of brachial impressions is impressed at theantero-lateral margin of the adductors.
Internal surface of the visceral part
can not be well observed, whiie at anterior margin, coarse spine-bases are to
be seen, which are regularly arranged
in two rows along the concentric bands.
Also in the portion of trail rather coarse
spine-bases are perceived.
Remarks.- The specimen figured by
IluA:--;G under the name of Spinomarginifera kueicliotcensis mut. a is hardly distinguishable from the present specimens
now in concern. HuA:-;G considered that
his specimen may be only a mutationof the preceding species. According tolh:A:-;G, S. kueichotcensis HuM-:G may be
distinguishable from his so-called mutation a in the following three points:
the latter is usually larger than theformer, does not show any marked
geniculation in ventral valve, andpossesses pustules rather sparsely arranged.
Besides, the less transverseshell form of the so-called mutation aand the presence of median fold, though
it may be sometimes indistinct, must

146

Koji NAK.4MUR.·lbe worthy of note. All those points
above stated must be taken into con·sideration in specific distinction. The
writer_ is now of the opinion that all
those points justly considering those
two forms specifically distinguishable
from each other.
The specific name. lwangi, is given inhonour of Prof. T. K. HcA:-;G who firstestablished the present genus.
Hdr.: Lower Kanokura series. Loc. :Kamiyasse, Niitsuki-machi, Kesennuma
city, Miyagi Pref. Reg. No.: 12370.
Co/f.: H. TAKEDA and K. NAK,u1VRA.
Reg. No.: 12369. Col!.: T. l\·IAEKAwA.
Loc.: I mo. Yahagi-machi, Rikuzentakada
city, Iwate Pref. f?eg. lv'o.: 12372, 12371.
Col/.: H. TAKEIM, l'vl. HARADA and K.
NAKAML:RA.

Bibliography
CIIAO, Y. (192i), Productidae of China. Part

1. Producti. Palaeontologia Sinica. Ser. B.
l·'asc. 2. Part. 1.
- - (1928). Producticlae of China, Part II.
Chonetinae, Productinae and Richthofeninae. Ibid., Fasc. 3.
DUNB,\R, C. and CoNDIIA, G. (1932), Brachiopoda of the Pennsylvanian System in
NelH·aska.
Nebraslw Geological Sun•ey!lull. 5.
T. (1932). Late Permian Brachiopoda
of Southwestern China. Palaeontologia
Sinica. Ser. B. Vol. 9, Fasc. 1.
MINATO, NL et al. (1954). Zur Biostratigraphie der permischen Formation desSetamai-GeHindesin
Si.id-Kitakami
Gebirgc. four. Geol. Soc. Japan, Vol. 60.
No. 708.
Mu11~-woov, H. (1930). The classification of
the British Carboniferous Brachiopod
Subfamily Productinae. Am1. 1l1ag. }lat.
His/., Ser. 10. Vol. 5.
SUTTO:", A. (1938), Taxonomy of Mississip·
pian Productidae. /our. Pal., Vol. 12.
WAAGEK. ·w. (1883), Salt-range fossils. PaHL'A:-.IG,/eontologia Indica, Ser. XIII.

Explanation of Plate 15(All figures in natural size.)
Figs. 1, 2, 3 and 4. Spinomargin~(era kueichou·ensis Hu A:"G .............................. p. 143
la. Internal mould of the dorsal ,-alve together with the internal mould of the apicalregion of ventral valve.
lb. Internal mould of ventral val\·e.
lc. External mouldof ventral val\·e.
ld. Lateral view of the "Steinkern ".
2. External mould of
dorsal valve.
3. Internal mould of ventral val\'e.
4. Internal mould of dorsal
valve showing the rather strong marginal ridge.
Fig. 1: reg. no.: 12!)-12: fig. -1: 12374. Imo. Yahagi-machi. Rikuzentakada citr. lwate
Pref.
Fig. 2: reg. no.: 1155-1; fig. 3: 12585. Kamiyasse. Niitsuki-machi, Kesennuma
city. Miyagi Pref.
Figs. 5. 6 and i. Spinomargin~(em lmanci :\AKA:O.IURA, n. sp ................ _...... _..... p. 145
5. External mould of dorsal ,·al\'e. 6a. External mould of dorsal valve.
6b. Internal mould of dorsal valve.
6c. Lateral view of the "Stein kern".
6d. Internal mouldof Yentral ,-al\'e.
7p.. Lateral view of the external mould of dorsal valve.
ib.
External mould of dorsal yal\·c.
7c. Internal mould of dorsal valve clearly showing the prominent marginal ridge. the muscle scars and the brachial ridges.
Fig. 5: reg. no.: 12369: fig. 6: 123i0. Kamiyasse. =-:iitsuk:-machi. Kesennuma city. l\Iiyagi Pref. Fig. 7: reg. no.: 123il. !mo. Yahagi-machi. Rikuzentakada city, .Jwate Pref.

NAKAMURA:

Spinornarginifera

Plate 15

3

lb

la

2
4

ld
lc

le

5

7b

6a

6d

K uMANoand NAKAMOTO photo.

Trans. Proc. Palaeont. Soc. Japan. X. S., 1\o. 35, pp. 1-17-155. pl. 16. Sept. 15. 1959

:370.

·· B!lKEVELLIA ·· AND .. EDENTULA '' FROl\I THE LATETRIASSIC l\II~E SERIES IN WEST JAPAN*
AJ\!RA TOKUYAMA
Geological Institute, University of Tokyo~VJ;~@()) ·• Baket•ellia ··(: •· Edentula ·•:&0' "Edentufa" triangularis'tiiile1!fP'Jf,~Jftl::.~@ L,.

~Vf.~iJ· C;. 37!1i'i1";.,"Gen•illia" hekiensis

r:lltn!ftjl:.;i!l;0t'l.\3!JJ:1m&U1:~~.ft~~~LI:o~~:!.::.'~Mil1i~i(lj:J13t:.y,m t,...

1li!'Jf:t~ -7 ~-?t:fi::Elit~H~r;:Z 1./'C'.' r.,,hekiensis O)~~EHIZI~"t'v)~ffi; . ~l'IJ=O)f!t:~iJ· 6 %;t -c' Jlt.filll.t Ballet!e/lia c rt)Jij~r: ~t«~ t 0t..:O)L'fifj.q Bakere/loides 'H~U§-t 7.>, X triallf(ltlaris 0~fH!dt. t;Jr:(llJJ(ltf)'pf;o)fl£(t::.,t 1). W.\.\CF.:"\ 0 Edentula (NITZCll r:3e!Ji>%lfi*;t1"lt•'.:>) !: Cox 0 Cunei·
gen•illia (Edentu!a 0~~ t r~ "l1Jl!ili§l ~l.t: :f):illij~())f!:!l:\:f!!it;l:'Jl1 7.>) c I!>*~EI'~l.:~? lf~f):!l!tl-?t:0"('. C0m\~~c:: Edentula O)fi;:-8 TVaage11ojJerna i>!Ji!Pii\-t;:,,iii!J. rll~F.I*

hitherto known from the South Alpsand japan. From the ontogeneticalobservation it is noted that .. Edentula ,.
is more closely related to Isognomotl
than Ba!?evel!ia. According to Cox 0954)
Cuneigervi!lia which is a subjectivesynonym of Edeutula \V.'<ACE:-: grows
through " Bal~eve/lia-stage " and therefore he referred it to the Bakevelliidae.
On the other hand ... Eden/uta .. triangu·
laris does not gro\v through this stage.
Its immature form bears an opisthocline
tooth in the anterior extremity andbears no lateral teeth in posterior. A
further difference between the two
species is in the ligament groove. !\lore
precisely. in •· Gervi/lia" helliensis a newligament pit which is triangular or
semiconical and prosocline. is inserted
on the posterior side of the area; later.
it is shifted fonYard till it becomes acompiete groove which is hemicylindri·cal and forms a right angle with thehinge line. In ·· Edentula" triaugularis
the ligament pit. which is narrow andlies at the anterior angle of the area.
becomes a wide and deep groove inposterior. Here the writer proposed a
new name TVaagenoPema tor the sub-"Gervil!ia" helliensis KoBAYASHI &IcHIKAWA and ·· Edenf1rla" triangularis
KoBAYASHI & IcHIKAWA are two ofabundant species in the Mine series.
The former is found in the bituminous
near-shore facies of the Hirabara stage
or the lower Mine series. \\'hile thelatter occurs in the neritic open-sea
facies of the Aso stage or the upper
Mine series. Several immature shellsof the two species enabled the writer
to study their ontogeny. Therefore
their phyletic relations are briefly discussed here. ·· Gervi!lia" hekiensis isincluded in a new genus Ballet•e/foides
or Agui!eria-section which bears pseudotaxodont denticles and distributes froml\Iiddle Trias to Cretaceous. So far as
the writer can see in his collection the
Bakevelliidae are not monophyletic. hecause this section differs from the
Ba!?et/effia-section in the dentition al·ready in the immature stage in spiteof superficial resemblances. "Ettentula '':VVAAGE:-.; is an Cpper Triassic genus* ReceiYed No\·. 12, 1958: read at theAnnual Meeting of the So.:icty at Tokyo,
Dec. 7, 1958.
147

Akira TOKUYAMA

148

stitute of Edentu/a WAACEN, 1907, (nonNITscH, 18~0) and he refers it to the
Isognomonidae.
The writer's thanks are due to Prof.
T. KoBAYASHI for his kind guidance andencouragement throughout this work.
Family Bakevelliidae KI:-<G

vel/ia- and the .lguileria-branch, whichwere independently derived from thePteria-stock and that the latter branch
is not a direct off-shoot from theformer branch. Therefore the writerestablishes a new genus Bakevel/oides
for the Triassic and Jurassic forms andAguileria represents probably a terminal
branch of this section.

!lgui!eria Section"Gervillia ·• hekiensis and its allies arevery common in the Upper Triassic
formations in the inner zone of South·
west Japan. 1\amely. "G." helliensis is
known from Heki (KonAYASIII & Icm·
KAWA, 1952). Nabae (NAK.\ZAWA, 1954)
and Kyowa (NAKA:xo, 1957) and Bakevel!ia
subhekieusis from Nabae. They are
fairly convex and almost equivalved
and have pseudotaxodont denticles, fair·ly wide, depressed triangular ligamentarea and a few but stout ligament pits.
In these characteristics they match with
Cretaceous Aguileria WI·IITE which isconsidered a subgenus of Bal?evellia by
Cox (1940). Some authors are of opinion
that these Triassic forms were derived
from the Bakevellia-stock (NAK.\ZAWA,
etc.) at one time and Agui!eria itself
was also derived from the same stock(Cox, etc.). In other words, the Triassic
and Cretaceous forms indicate two
independent branches. HAY,\~~~ (1957)
and NAKA:xo (1957) are of opinion thatthe two forms are on the same lineage
from the stock of Permian Bakevellia s.
str. Some immature forms of the Mine
series, the writer col Iected recently,
have pseudotaxodont dent it ion alreadyin the very immature stage, while the'' Bakevellia-stage ., having two prosocline teeth at the anterior angle cannot
be seen in this form. Therefore thewriter thinks that the Bakevelliidae
include at least two branches, the Bake-

Genus Bal?et•elloides ToKUYAMA.
new genus

1)Pc species:-" Gen•i!lia" hekiensis KoBAYASHI & lcnmAwA from Carnic Hekiformation in Japan.
Diagnosis :-Sheli almost equivab•e.
fairly convex and roundly triangular;a very shallow sulcus separates theanterior part from main body in left
valve. Ligament area wide. depressedtrigonal or trapezoidal. with a few,
stout ligament pits which are radiatingfrom umbo. Hinge area narrow, withpseudotaxodont clenticles.divergent fromumbo: posterior one or two denticles
sometimes become lateral teeth. Pallial
line marked by a series of pallial muscle
scars in anterior part.
List of species :-Gervi/lia mytiloides
ScHLoTHEI~I by CRED~ER (1851) from thelower 1\Iuschelkalk. Gervillia lata Puu.LIPS by KEYsERLINc. (1846) from the Jurassic of Petchora district.
Remarks :-In the outline, ligamentand hinge apparatus Cretaceous .A.gui/eria
WuiTE is the closest ally to this, although WniTE's is distinguishable fromthe writer's by the more obliquelyelongated outline and more profoundsulcus in the former than the latter.
?vloreover, the posterior lateral teeth
are not separable from the pseudotaxodont denticles or a series of "transverse
crenulations '' in !lguileria, while they370.

Triassic ·· Ba!?evelfia" and .. Edentula"

are fairly stout and well specialized
from the denticles in this genus. Therefore Aguileria is more widel.y apart from
Pteria than Bakevelloides or more specialized than Bakevelloides, if Bakevel/oides and Aguileria are in the same
evolutional lineage. although ignoranceof the growth change of Aguileria is a
defect to determine the true relation.
In spite of the superficial resemblances
this differs from Bal?evellia in the hinge
development. According to Cox '·In a
few forms (subgenus Aguilcria) the
greater part of hinge line is bordered
by a series of narrow transverse crenulations ". In Bakevelloidcs. however.
these actinodont denticles are alreadyrecognized in the very immature stage
as will be related later. Therefore
they reveal the true dentition insteadof mere crenulation. From the ontogenetical stand point the dent icles are
essential for this branch. Its immatureform closely resembles Pteria. P. okuhatensis for example. in outline and in theligament pit. Therefore this may havebeen derived separately from a pteriid
branch rather than from Bakevellia.
Finally. the writer opines that the
Bakevel!iidae are not monophyletic but
include at least the two branches.
Bakerelloides /iel?iensis (KoBA Y ASH r
and IcrJJKA"'A)
Plate 16. Figures 1-7: Text-figure

1926. Gerrillia sp .. OZAWA, f. Ceo/. Soc. Tokyo.
vol. 33, p. 208 (listed).
1938. Gervillia sp., KATAYA~tA, Ibid .. vol. 46,
p. 138, pl. 8, fig. 11 (no description).
1952. ·· Gen•illia ·· hekieusis KouA Y ASH 1 & Ic H 1KAWA. f.]. G. G., r·ol. 22. pp. 76-78. pl. 2.
figs. 4-6.
1954. Baket•ellia hekiensis, NAKAZAW A • .l!em.
Col. Sci., Uniz·. Kyoto, ser. B. vol. 21, pp.
~Hi-219, pl. 5, figs. 3-8: pl. 6, figs. 1-3.

14~)

1954. Baket•ellia sub/Jel>icnsis NAKAZAWA. ibid.
!'0/. 21. pp. 219-220, pl. 6, figs. 4-7.
1957. "flguileria" hekiensis, NAKA:o-;o, f. Sci.
Hiroshima Unit•., ser. C. t•ol. 8. p. 64. pl.
9. fig. 4.

Descriptiou :-Shell fairly thick. roundly and obliquely trigonal, transversely
elongated and more or less inequivalve.
with left valve more inflated: umbo
prosogyrous, large, rounded and protruded above hinge line: anterior margin rounded: antero-ventral almost
straight with or without a weak ventral
sinus at '2/5 from the anterior extremity:
this sinuation more distinct in left valve
than in right: posterior and posterodorsal margin moderately com·ex. oblique to dorsal margin. Both anterior
and pos·,erior auricles indistinct: posterior one slant and a little comce'X.
Surface marked with weak and somewhat regular concentric growth lines.
Adductors anisom}'arian: posterior adductor impression large and subelliptical. while anterior one is subrounded:pedal retractor scar deep and distinct
under umbo: pallral line distinctly
marked by a series of pallial muscular
impression in anterior part. Ligamentarea fa!r!y wide. low triangular to
trapezoidal. stria ted horizontally: ligament grooves 4 to 5. large. deep andlonger than wide. Hinge area natTO\\·,
provided with pseudotaxodont denticles.
divergent from umbo. Posterior one(left valve) or two (right) form stout
and oblique lateral teeth.
-------

Jleasuremeut iu mm.
----

--

!Length Heigh~[------

One-pit stage (fig. 7)
Two-pit stage (fig. 6)
Two-pit stage (fig. 5)
Three-pit stage (fig. 3)

12~

to~

18. I
23.4

14.6

35.5

Three-pit stage (fig. 2)
Adult (five-pit) stagc (fig. 1)

49.5
5" .,

32.0
36. i

(,.J

10.9

43+

1511

Akira TuKULIM:lObsen·alion :-~.Jany specimens in the
Mine collection are fairly well preseryed. Their outiine. ligament and others
Yary so widely that the writer thinksthat ltekiensis and subhe!?iensis (~AKA-

zA ,,. A. p. 220) belong to a species where
sublu,l?iensis represents a primitive stage.
The growth changes observed in the
Mine collection are:Tcxt-iigure: Baket•e!loidestransformation of
hinge and ligament groo,·e,in -l ontogeneiical stages: a:one-pit stage. X~: c: eariy
two-pit stage. X~: d: later
two-pit stage. X 2: b: threepit stage. X 1.

ltekie11sis:

One-pit stage :-A ligament pit
the beak is prosocline. triangularand like that of Pteria. Several small
teeth distinct in the hinge area ar.:::arranged in ·• actinodont-type .. dentition.
2) T,,·o-p!t stage :-The lir,~t pit. justbelow 1he beak is prosoc Ii ne and su htrapezoidal: the second pit added in theposterior part of the ligament area: noremarkable change is seen in dentition.
although the denticles become somewhat
obsolete in the middle part. Later theshell is elongated obliquely: pallial line
and antero-ventral sinus are more distinct; second pit is shifted to the middle.
3) Three-pit stage:-The third pit
inserted in the posterior part of theligament area is triangular and prosocline. while the first and second areparallel to each other and rectangula;·to the hinge: the interspace bet weenthe. first and second is narrower thanthat between the second and third. Ligament area is striated trans\·crsely. The
lateral teeth are clearly separated jnto
t\\'O series by the non-denticulate median part. although denticles sometimes
1)

un~lerform a continuous series.
4) Adult stage :-Ligament area depressed. slightly incurved. striatedtransversely and forms an obtuse angle(about 120°} with the plane of commissure: pits number -t or :i. Dentition
composed of se\·eral anterior denticles
and 1 or 2 oblique posterior teeth.
Its immature form closely resembles
Pteria such as okubatemis from thelower l\·line series. in outline and ligament pit. Its newly inserted pit is very
similar to that of Pteria in the shapeand prosocline state. Seeing that someprimitive Pteriae are similar to this (ex.
Cyrtodonta derlivis) in dentition, this species grows through the "Pteria-stage", BF.R:--1.-\.Ro·s .4t•icula-stage' rather than the·· Ballel'ellia-stage" iFRECII. 19021. Therefore the group of Balm•e!loides may havebeen derived separately from the ptcriid
stock rather than from the Bakez•elliastock. Accordingly this group should be
distinguished from the group of thestrict sense at least in the generic rank.
Comparison :-In comparison with thetypical form from Heki. the :\linespecimens are commonly more convex

370.

Triassic ·· Bakevellia" and ··Eden/uta"

and more obliquely elongated. Fromany other specimens hitherto describedfrom 3 places in West Japan. the !\lineform is distinguishable by the convex
outline and more" primitive" features:
namely, anterior and posterior adductor
scars are simple and large. Such differences. however. bear no specific \·aJue if
considered the wide variability in outline. hingement. dentition and interior
among the l\Iine specimens.
This species resembles Baketellia antiqua (l\k:-;sTERl by KI:-;c in outline andinterior. but the resemblance may besuperficiaL because their hinges arequite different from each other alreadyin the immature stage. "Gervilleia ··myti/oides ScnoLTHEI:>.I in CREn:o;ER fromthe l'vfuschelkalk may belong to Brtlwvelloides, although that species is more
obliquely elongated and less distinct inauriculation.
Jurassic Gervillia lata
Pnli.I.IPs by 1\EYSERI.I:-~c from Petchora
district may be the closest all~·. It isalmost indistinguishable from the typespecimen of hekiensis except for the
deeper posterior muscular impression
and more rounded anterior angle in thelatter. Generally speaking, however,the Jurassic form differs from this in
the more equi\·al\·ed shell and morerounded outline. less distinct Yentral
sinus and better defined posterior auri·cles. Finally . .·1guileria cumminsi \V H 1TE(in STEPIIE:-:so:-:. 19:J2; type species ofAguileria) is intimately related tu thisin dentition. hinge. pallial line andmuscular impressions. but WIIITE's ismore obliquely elongated and has adistinct byssal sinus. Because the byssal
character ,,·hich may be essential forclassification. is widely apart between
this and .4guileria. the writer refrainsfrom identifying them to the same
genus. Their true reiation is indeter·minable until the growth cha.nge of151

wmminsi is well known.
Occurrence :-Common m the upper
part of the Kumanokura or the middle
Atsu stage at West Shirogawara andYery common in the middle and upper
part of the H irabara or the lower i\Iineseries at Shiraiwa. i\Iugikawa. Hirabara
and Okubata (from N to S). At Shiniiwa
this species forms a shell bank withlarge Palaeop/iarus, •· Gryp/wea ". Schalhiiul/ia and other near-shore pelecypods
in bituminous sandstone facies. At Mugikawa it forms a shell bank by itself in
more or less bituminous sandstone. At
Hirabara it nccurs in a shall bank with
Pa!aeopharus and Minetrigonia in shallowsea sandstone. At Okubata it is somewhat scattered in shallow-sea sandstone.
Here this species is restricted to thenorthern or inner half of the .. Hirabarabay .. (Tni<t'Y.nt.\, 1H58). The mode ofoccurrence suggests that this species ischaracteristic of the bituminous or nearshore shallow-sea facies. In Held, Nabae
and Kyowa this is often associated with
Palaeophams ..Hinetrigonia and Cardinia
and sometimes with Lima or Oxytoma.
Family Isognomonidae D.\LL
Genus TVaagenopenuz ToKI'Y ,, \I.'\.
new name=Edentu/a WAAGE:\, 1907
(non "\'JTZSCH. 1820\
Type species :-Edentula latepfanata WAI rom Carnic Pachycardientuff ofSeiser Aim.
Diagnosis :-Shell fairly large. flattened and almost equivalve: anterior wingsmall and posterior one broad and scarcely defined. Byssal opening distinct
below beak. Cardinal and lateral teeth
absent alreadv in immature stage. Ligament area shorter than dorsal margin,
AGE"

152

Akira ToKU l'rlM4

striated transversely and provided withseveral ligament groo\·es. mostly wider
than high, small and narrowly spaced!lear anterior angle. tending to be larger
and more broadly spaced posteriorly.
Posterior muscular impression at theend ot ligament area. large but weak.
while anterior one is small and distinct.
Surface covered with concentric linesof growth: no radial markings.
List of species :-Gerrilleia plana/a BRo·
ILI, Carnic, South Alps: Edentula ozarcai
KonAYASJII, Ladino-Carnic. Japan: Eden·
tufa tria11gularis KoBAYASHI & lcJJJI<AwA,
Carno-~oric, Japan.
Remarks:-The genus Edentula was established by WAAGE:-; for :? Carnic spe·
cies. Subsequentl~7 ~species were addedfrom Japan. As the generic name Ede11·
tufa vVAAr.E,-.; is preoccupied by N!TzscH
in 1820. Cox established a new genus
Cimeigen•illia for its substitute. selecting Gerl'illia lzage11ott'i as the type spe·
cies: Cnx's, however, bears a larger andmore distinctly defined posterior wing
and a less distinct anterior wing than
WAAGE:-~'s.
In the Liassic form "thehinge in the earlier growth-stage with
two teeth in the anterior angle and an
elongated tooth on the interior of theposterior wing··. Thus Cwzeigen·illia
grows through the '' Bakevellia-stage ".
Hence Cnx assigned it to the Bakevel·liidae. On this occasion W ,uGEN's t \\'O
Edentulae were referred to this genus
beside 3 Liassic species.
A study on the growth of hinge teeth
casts a question whether Edentula is re·ally identical \Vi th Cuneigercillia or not.
More precisely. the writer's "Edentula"·collection shows that hinge teeth, especially posterior laterals. are absent already in the very early stage. Its outline changes from cuneiform (immature)
to Isognomon-shape (mature). So far as
the writer can be seen in the Minecollection. triangularis does not growthrough the Bakevellia-stage. If does,it should be called ·' Pteria-stage" rather than "Bal?evellia-stage ''. Moreover.
ligament apparatus suggest wide difference between the Triassic and Jurassic
form. Triangularis is widely apart from
Cuneigen•illia hagenozri. while it is congeneric with lateplanta and planata* inthe above mentioned characteristics,
they are more close!~' related to lsognomon rather than Baket,ellia. Because thewriter has no opportunity to make aclose study on Czmeigert!illia, it is a question for him whether or not all of theJurassic Ctmeigerci!liae differ from.. Edentula" in the generic rank. ~e,·er­theless it is certain that Eclentula' latep!anata canno! be maintained in Cuneigerri/lia. Therefore the writer proposes a
new name TVaagenop?.ma for the substitute of Edentula W.\AGF.:>:.
As for its phyletic relation, WAAGE:>:suggested the lineage of Myalina (orPromya!ina)-Hdenfula-Isognommt. According to him the embryonic hinge developmen·:: of lsogmmzon is also suggestive of 1vlyalina as the ancestor. On theother hand Cox took Cuneif!ervillia for aderiYative of Bakevellia. With the !\linecollection, it is found that immature
hinges of IVaaKenoperna and Bakevelloides
are quite different. Namely, the posterior lateral is absent in triangularis,
while it is ver~r stout and distinct inltekieusis: ligament area shorter thanmargin in Waagenopenza. while it is aslong as the margin in !Jakellelloides. An
anterior tooth is opisthoclinc in Eden/uta,* The writer could obsen·e the replicaof BHOILI's type specimens which were repro·
cluced by Prof. T. KoHAYASIII at the Institut
flir Palaontologie und historischen Geologic
der Ludwig-i\laximilans-Universittit zu Miinchcn through the courtesy of the late Prof.
F. BROIL!.

370.

Triassic ·· Baker,te/lia" and .. Edentula"whereas 2 cardinal teeth are prosocline
in Baket•e/loides. The arrangement ofthese hinge teeth, commonly prosocline.
must be essential for phylogeny. Thisis the reason why TYaagenopema is placedin the Isognomonidae.
Distributio11 :-Upper Triassic: South
Alps and Japan.

rraageuopema triangularis(KOBAYASHI & lcHJKA\\'A)
Plate 16. Figures 8-15
1952. Edentula (?) tria11gularis. KoB.\Y ASHJ &ICHIKAWA. ].]. (;.G .. t·ol. 21. pp. 268·270. text-figures 1, 2.

Description :-Shell almost equivalve.
11attened, broadly inf.ated. depressedtrigonal to cuneiform. wider than highand widest at a little below hinge line:
umbo a little protruded above hingeline. Anterior auricle small, distinctly
defined in left valve and less distinctly
in right: posterior wing broad and illdefined. Byssal sinus more or less dis·tinct. Antero-ventral margin almost
straight except for byssal sinus: posteroventral one broadly rounded. Ligamentarea short and narrow in immature. becoming longer and wider: ligamentgrooves widely spaced. wider than long.
shallow outside and deep inside, small
and narrrnv!y spaced in the anterior
angle. becoming larger, wider and more
widely spaced posteriorly. Hinge withan oblique prosocline tooth in anterior
angle of immature shell, but later it
1l!easureme111 in mm.
Immature stage (fig. 16)
Immature stage (fig. 15)
Middle-grown stage (fig. 13)
Mature stage (fig. 9)

Length Height
10.3
16. 5

:!6.9
65.5

6.5
10. 0
11.5
52.0

153

becomes suddenly obsolete. Posterior
lateral absent from very young stage.
Posterior muscle scar large and subrounded. Surface marked with concentric lines of growth.
Observation :-The Mine specimens in·elude several growth stages but no nepionic stage: their growth changes are:1) Very immature stage :-Outline is
Pteria-like: anterior tooth exists in an·
terior angle. but posterior lateral tooth
is absent: ligament area Yery narrow:
ligament groove unknown.
2) Immature stage:-Trace of an anterior tooth is opisthocline in anterior
angle: ligament area narrow and short.
about half as long as dorsal margin:ligament grooves 3 or -l. widely spacedin posterior: most anterior groove short.
narrow and a little oblique: all of themwider than long. arch-shaped. deep in
inside and shallow in outside of hinge
margin.
3) l\'lature stage :-Outline a little high·er and more rounded: hinge area fairly
broad, as long as anterior margin: ligament grooves 5: each wider than longand narrower than interspace: ligamentarea becomes wider and longer throughgrowth: ligament pits small, narrow andnarrowly spaced in anterior angle. becoming larger. wider and more widely
spaced in posterior part.
ComParison :-Gen•illeia Pfanata BRoiL I
is very close to this species. Its middle
stage of growth is almost indistinguish·
able from the illustrated species by
BROILI: they are all cuneiform in outline. narrow and more or less short ligament area and similar ligament grooves.
In the full maturity it is. however, higher and more broad)~· rounded in thisthan in p!rmata: anterior auricle smaller than in plana/a. Edmtula /atep!mwta'iV AAGE:--~ agrees with this in ligamentand outline but \V.-\A.Gr-::--;'s is more broad-

154.4kira TOKUY.·I.\1.\

ly inflated and more rostrated anteriorly. Edelltula ozmmi KoB:\ Y:\SIH (1935) isdistinguishable from this by the protruded posterior wing and higher outline in the former than the latter. Skytic Ede11tula castelli , .. W ITTE:snt~RG (1908)is widely apart from this in the longer
and more oblique outline in the former
than this. Its generic designation for
Edentula is questionable. Cuneigervillia!zagenowi is distinguishable from this in
the more strongly defined posterior wing
and Jess distinct anterior auricle. The
Jurassic form takes the aspect of Bakevellia in the immature stage, but thisis quite distinct from that genus already in immature stages. notably inthe hinge de\·elopment and ligamentcharacters.
Occurrenc!!: :-Common in the middle
part of the Aso or upper i\linc series(upper Carnic to Carno-Noric) at Aso,
Kami-yuguchi, Higaeribara, Sonose andlchinose, a;l in the l\Iinc area in Nagato.
At Aso and Kami-yuguchi it occurs with
Eummplwtis, Lima, Ento!ium, Clzlamys.
Cardinia, "Gryphaea " and other pelecypods in very coarse sandstone of littoral
neritic facies. At Higaeribara it forms
a shell bank with .. Pentacrinus". Eumorplrotis, Plagiostoma, Chlamys, Tosapecten.
Plicatula, "Gryphaea" and other pelecy-

pods in medium grained sandstone ofopen-sea facies. At Sonose and Ichinose
it occurs rather scattered in very coarse
sandstone, Iike at Aso. with AnodontoPhora, Tosaperff'n, "Gryplwea '' and otherpelecypods. The mode of occurrence
suggests that this species is characteristic in the shallow open-sea facies andmore off-shore in comparison with the
Bakeve!loides- facies.
As Kon,,y,,slll described. Edentula ozazmi is very common at a locality westof Shirogawara in the upper Atsu series(Ladino-Carnic or lower Carnic). It isinteresting that Waageuopema is absent
in the Hirabara stage (lower l'viine series;
lower Carnic) notwithstanding the fact
thaf the Hirabara stage yields many
neritic pelecypods and brachiopods.
It is important that this is an only
species occurring in common between
the .\line and 1\ariwa districts. In the:\ariwa district !KoBAYASHI & IcHIKAWA
1952 bl it is associated with Cardinia
mismcensis and ·• Gen,i!lia" saekii. This
represents a marine hand inserted a little lower than the Entomrmotis-bed. Its
age is Noric, while in the ?\line area
this species occurs in the upper Carnic
to Carno-:\oric Aso stage. Therefore
the range of this species is from upper
Carnic to :\oric.

Explanation of Plate 16
Figs. 1-7: Bakevelloides hekie11si.~ (KnnAY:\~111 & lci!IK:\1\'A) ............................ p. 1-19
1-2: Right internal mould of an adult shell, X l: 3a, b: right internal mould (3a) andits clay cast (b, c) of 3-pit stage, x1: 4a-c: Left internal mould (lateral (a) andanterior view (c)) and its gypsum o;ast (c), x1: fi: later state of two-pit stage, x2;
6: earlier state of two-pit stage. x2: 7a, b: one-pit stage, x:~. Loc.: 1: Hirabara, 2, 5, 7:
North of Om inc station: 3. 4: Shirawa: 6: Okubata: all in the :\Iine city, Nagata.
Figs. 8-16: Waogenoperna triangularis (KOBAYASHI & lciiiK ..\WA) . . . . . . . . . . . . . . . . . . . . . . p. 153
8-12: Adult internal moulds, x 1: 13, 14: middle-grown stage, x 2: 15, 16a, b: immatureleft internal moulds and an external clay cast of a left valve (b), x3. Loc.: 8, 9, 12:
Mishimc, near Aso; 10, 11: near Sonose: 13-16: Higaeribara: all in Aso, Mine city inthe upper Carnic Aso stage.

ToKUYAMA:

Triassic .. Bakevellia" and ·• Edentuta"

Plate 16

370.

Triassic ·· Bakevellia" and ·· Edentula"

Heferences cited
BIWIJ.I, F. (l\l04): Die Fauna der Pachycar·
dientuffe der Seiser Alp. (mit Ausschluss
der Gastropoden und Cephalopoden). PalaeOirtograph., Hd. 50, S. 145-~27, Taf. 17-27.
Cox. L. R. (1940): The Jurassic Lamellibranch
Fauna of Kuchh (Cutch). Pal. Indica, ser.
9, t•ol. .1, pt . .1. 157 pp., 10 pis.
- - (1954): Taxonomic Notes on Isognomonidac and Bakevdliidae. Proc. J"!al. Soc.,
vol. 31, pt. 2. pp. 46-49.
C!<EONF.I<, H. (1851): Ober die Gervillien der
Triasformation in Thiibingen. N. ]b. f.
Mi11. usw .• ]g. 1851. S. 641-657.
Fr~ECII. F. (1902): Ober Gervilleia. Zentralb.
f. Mi11., ]Jr. JY02. s. 609-620.
H.\YA!\11. I. (1957): Liassic Gervillia and !so·g11omon in japan. Japan. ]. Geol. Geogr.,t•o(. 28. pp. 95-106. pis. 6, 7.
KE YSERl.ING, A. G., (1846) : Wissenschaftliche
Beobachtungen auf ciner Reise in das
Pdschora-Land, im Jahre llH;t 465 S., 2~
Tab. St. Pdcrsburg.
1\.11\G, W. (1850): A Monograph of Permian
Fossils of England. 258 pp., 28 pls. Pa/aemrto;;r. Soc. London.
KouAYASIII, T. (1935): Einige neue Triadische Bivalven aus der Innenzone Siidwestjapans. japan.]. Geol. Geogr., t•ol. 12,
pp. 27-32. pl. 7.
- - & K. !CIIIi';Aw A (1952a): The Triassic
Fauna of the Ileki Formation in the155

Province of Tamba (Kyoto Prefecture),
Japan, Ibid, vol. 22, pp. 5G-84, pis. 1-3.
& - - (1952b): Some Late Triassic
Fossils from the Nariwa District in Province of Bitchu (Okayama Prefecture),
Japan. Ibid, pp. 261-274, pl. 10.
Ni\KANO, M. (1957): Carnian Fossils from
Kyowa, Okayama Prefecture, japan. ].
Sci. Hiroshima u~riz• .• ser. C, z•o/. 2, pp.
63-67.
NAKAZA\\·A, K. (1954): A Study on the
Pelecypod-Fauna of the Upper Triassic
Nabae Group in the Northern Part of
Kyoto Prefecture, japan. Pt. 2, Bakevelliids etc. Mem. Col. Sci., U11iv. K)oolo,ser. B. t•o/. 21. pp. 213-222, pis. 3-6.
STEPHE:-.:so:-.~, L. W. (1952) :Larger I nvcrtebrate Fossils of the \Voudbine Formation (Cenomanian) of Texas. U.S. G. S.
Prof. Pap. 242, 226 pp., 59 pis.
ToKUYA~lA, A. (1958):
Die obcrtriadische
Molasse im Mine Gebict Wcstjapans. 1.
Tcil: Stratigraphic und Werdcgang. ].
!.col. Soc. ]ajxm, vol. 65, pp. 454-463.
W AAGDI, L. (1907): Die Lamcllibranchiaten
der Pachyl::::·dicnluffc dcr Seiser Aim
ncbst vergleichend paliiontulogischcn
und phylogenetischen Studicn. Ablr. k.k.
Geol. R.-A., lld. 18. 11.2. S.l-180, Taf. 2534.
\'. WlTTENBL'lH.i, P. (1908): llcitr:igc zur
Kenntnis dcr Wcrfener Schichtcn Siid·tirols. Geol. u. Pal. Ablr., NF. Bd. 8, S.
251-289, Taf. 36-40.

PROCEEDINGS OF THE PALAEONTOLOGICAL SOCIETY
OF JAPAN
rFt*?;1o~~!n72lill#lJ~J

I959if.2JJ 14 a

1A~*~111l.'itfl!S jJ!!'t'!~f: g~~ll~n.:.:to~f~o (~~~ 32 f,),·-crmmn.

{;ll~t.:.:tol't.O~Jlii~~tH::.llM:

ili{~ 8 1-.J:~U)jlfi IJ "('it'> .Q o

Fusulinids from the Aratani Conglomerate
in the Northeastern Part of Yamaguchi
City ................. Michihiro K.'\wAr-;of:chigoel/a, a new Permian fusulinicl genus
frolll the Upper Part of the Omi limcslunc, Niigata Prefecture, japan (ti:;iV\;)............ , . . . . . . . . . . . . . . . Hisayoshi !Go:R1,tt ~~t~l.:./n'~ .O.!lliltiUII 1!1fl!'N•C1) ~i.fl!!l<tt~> ............................ tfm'Dim

Some Miocene Foraminifera from Okayama, Hyogo and Kyoto Prefectures, West
Japan........... Yoshiro TAl
Smaller Foraminifera from the Tanabe Miocene Formations. Wakayama Prefecture.............................. Yoshiro TAl
Permian Corals from the Taishaku DiMrict,lliroshima Prefecture. Japan ........... .
. . . . . . . Tsuruo Yol,o\·.,~1.\
f~AA f~l.'ll i\ 'ff\';lllftt1Jl:!£:1fjC1)Ji¥.!.1Wl~.:.-?l.t'lfi(i-c (i!lc;IIIA"/) ( IU.t)· ..... -~~·;j~!"~liJ:_:_:

Bemerkungen tiber (kn Brachiopodenfazies
dcr Torinosuscrie Sudwestjapans (f~ob\:)........... Akira ToKUY!UIAOn Some Ordovician Fossils from Northern
Malaya and her Adjacence ............. .
................. Teiichi KonAYASIII
lllll~in!Cfff~ (\5JT~r!Jil4)j) J: 'J Mono/is (Entomonotis) (1)..i'fillW ... ............... J.i:fi. jY;
Marine Jurassic Pelecypods of the Tetori
Group in Makito Area of Northern Gifu
Prefecture. Central Japan ( (~;OC) ...... ..
..... Itaru HA YA:-11
Taxodonta and Isoclonta from the Upper.I urassic Soma Group in Japan <1\:n'l'O ..
. .. .. .. ..
. ........ Minoru T,\!\ltJRA
Upper jurassic Ptcriacea from the Soma
Group in Japan ({~itt) .... Minoru T.->.li.WRA
A Note on Neoburmesia, peculiar Shape ofUpper Jurassic Pelecypods, with Descrip-

U;.l;:b!±.f~¥=~~ 73 lill!71J~:.t 1959.$5FJ ~3 B
111ii:k•f-.I!I!'T-1$jjjj~:f:~~'V001lli [., t~. (~~~- 25

i'])q~ glj ~IIi (J!tii1:{\; · rll~cf~T:il~~v-:>*~'fdLI: ..... -iidllffi.Jlm{j-:fJIJ ~ t.!IJ iJ.it

On the Upper Permian fusulinids from the
Ogamata formation, Northwestern Partof the Kwanto Massif (f\;';.flJ;) ........... .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Atushi Is1111
New Species of Paleogene foraminiferafrom Kumamoto Prefecture ........... .
. . . : . . Shigeo MuRAT.-\ and M. SUGAHARA
A Gotlandian Coral newly found in the
I-IOei Mine, Oita Prefecture. Japan ..... .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . Mitsuo NooA
Note on the Gotlandian Tetracorals fromthe Fukuji Formation. Part 1. (ft,M:) ..
....................... Ilisayoshi IG6
On the taxonomic Position of Faz•osites
hidensis and its Devonian Age. (fl;lfiC) ..
. . . . . . . . . . . . . . . . . . .... Takashi Hr\1\IADA
Upper Paleozoic Corals from Fukuji, Southeastern Part of the Hida Massif. Part 3.
((~;t4;) ...................... Ilisayushi lG<ii;\ IIJ~Ij!-)j( ~ l~;tlJIIJ~'lvJ.Qii!lt f,i[(t (::iiC '? ~ '"C ((I;;I{JG) . .............................. ' ~~·,j· fifijlhl=:

On the Discovery of Gunialitic Ammonite
from the Upper Visean I-longo formation,
Ilida Massif. ({\::~) ........ Ilisayoshi leo
New occurrence of Solenoceras in the Sa·
nuki Mountain-range, Shikoku, Japan.

lion of Mytilids and Myac.:ids from theJurassic Soma Group in japan (f\:.t-JC).......................... Minoru T.·\~IUR!\
lleterodonta and a Ust1ea from the Upper
Jurassic Soma Group. Japan ((\;~~) ....
. .................... Minoru TA~WRA
li\IIJ ~~~IW.fr~IJ)::O:ff] fHti'i (1)= ·31\RI.:. "?l, -c ..

· .................. · · ............ · 'l'!fJU~I
A New Locality of the Vicarya Fauna from
Aomori Prefecture (t~:OC) .. Takehiko IwAI
On FortijJecten kenyoshiensis Suo.\ & SI-llnATA (MS) from the Pliocene of Aomori
Prefecture, Japan (fl:;l\7't) .. Kiyotaka CIIINZEI
ltfi1J 1 ;:r..J::ij(1).~f!O)IliO'ill.:."?~·-c ... -l!tiJl ~On the Fossil Beech Leaves from the Ningy6-t6ge area in the Chugoku district.
Japan (fl;;lfA;) ............ Toshimasa TAN AI
On a Cycadean Trunk from the Uryu district, Hokkaido. Japan ( f\:liJt).
........................ Toshimasa TA:>~AI..... l\litsuo NAKANO and K. Nu~>IAI'O?WE Desmoceratidae f.'f-1<::.![ ~fl.~ ffttl'ii.tl~- .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . tNBfm1::
Upper Cretaceous Ammonites of California.
Part 2............... Tatsuro MATSl'MOTO
Daonella in japan. (f~lb'e) ............... · · ·.. Teiichi KOBAYASIII and A. TOKI.iYA~>·IAThe Halobiiclae from Thailand. ({~ilk) ....
.. Teiichi Kon.\YASIII and A. TOKUY:\:\1.-\Upper Jurassic Pelecypods from the Tori·nosu Group in Shikoku, japan .......... .
................... Minoru TA~tt:RA
The Bearing of the Trigoniids on the Jurassic Stratigraphy ofJapan (Studies on theJurassic Trigonians in japan. Part 8.) ..
.................................... Teiichi
KoBAYASHI, K. MoRI and M. TA!-.IUR:\~grl{tEJ!!JJ¥Jli'tl.: '? ~ '-r (ft;V\:) ........... · . ·. . . . . . . . . . ~!l-lf::::ll~ · .f'Aff~U.!!.
'Ml'Pf4ilmlll~ Pectinidae IC:: '? r, '"( •....• Eill'!iO~!J!l'Eflfiiljfi!'llff~ Veneridae 1::: '?t ''l...... gllffi.(J.:!JJ'IJdfoll/g-jllfi!f Buccinidae !C: '?t '"C ...... f!JM!{j(!fJ
tl/ii..I~O)I·I•!f!Ji!!Ji!¥.0~ ft:fil<:: '?P "C (ftliJt) · .... ·.................................. W::iq~!fB
Younger Mesozoic Estherids from the
Wnkino Group in Northern Kyushu,
japan............ . ..... Hisashi KUSUMITwo New Species of Kewia from Japan. (f\;,ik) .................... Malsutaro SHIBAT.\
J\'otcs on Microfos~ils from a t:alcareous
Sandstone (probably Pleistocene) at Kiribenohara, Yuya-machi, Yamaguchi Prefecture ............................... .
. . Kazuo OI<,\1-IOTO and Wataru lsHIJI~IA

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CONSTITUTION

of the
PALAEONTOLOGICAL SOCIETY OF JAPAN
Article I. The Society shall be known as the Palaeontological Society of Japan.
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Article 14. The Society. by decision of the Council. may expel from membership persons
who have failed to pay the annual dues or those who have disgraced the Society.
Article 15. The officers of the Society shall be composed of one President and fifteen Councillors. among whom several shall be Executive Councillors. The term ofoffice is two years and they may be eligible for re-election without limitation.
The President may appoint several persons who shall be Secretaries and Assistant Secretaries. An Executive Council shall be nominated and approved by
the Council. Councillors shall be elected from Fellows by vote of returned mailunsigned ballot.
Article 16. The President shall be a Fellow nominated and approved by the Council. The
President shall represent the Society and supervise the business affairs. The
President may appoint a Vice-President when he is unable to perform his duties.
Article 17. The Society may haYe the honorary president. The honorary President shall berecommended by the council and approYcd by the General I\'leeting. The honorary president may participate in the Council.