TheThemalacological malacological society of Japan

TAKI:Chiton Fauna of Japan (1) 341

Tesch, J.J. 1904. The Thecosomata and Gymnosomata of the Siboga Expedition. Siboga Monogr. 52, 92 pp., 6 pls. 1913. Das Tierreich. 36 Lief. Mollusca. Pteropoda. 16+154 pp. -- --- 1946. The thecosomatous Pteropoda, i, The Atlantic. Dana Rept. 28,

82 pp., 8 pls. - 1948. The thecosomatous Pteropoda, ii. The Indo-Pacific. Dana Rept. 30,

45 pp., 3 pls. in Tokioka, T. 1955. 0n some plankton animals collected by the Syunkotu-maru May-June 1954, iv. Thecosomatous Pteropoda. Publ. Seto Mar. Biol. Lab. 5 (1), pp.59-74, 7 pls. des Vayssiere, A. 1915. Mollusques Eupteropodes provenant des campagnes Camp. Scient. Albert ler de yacht Hirondelie et Princesse Alice. Res. Monaco, 47, 224 pp., 14,pls.

-c -V' -:) Eil Xg iilill }: t7 ti" 1 3till re e'zz. vN

?i･ir-･ tsE ･t.-: "G 'L JI{ Jkij )k( e-IJ: lk 21 lfl} i }]i' l･g yt< rXr,,. FtF

On the Chiton Fauna of Japan (1)

The Status of Ischnochiton comPtus and L boninensis

Iwao TAKI Animal Husbandry, Department of Fisheries, Faculty of Fisheries and Hiroshima University, Fukuyama, Japan

(firX Text-figs. 1-6) to the Though my elder brother Isao Taki (1898-1961) devoted himself study of the fauna of Japanese Chitons and published a number of papers in this field

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342 VENUS:22 (4) 1964 '

I am very to those grateful gentlemen who have sent valuable Chiton specimens to my brother at various occasions from various localities. It is a pity that all his scientific property (specimens, liteirantures and notes) was practically lost by the War Il[which has been col!ected and piled up for many years (during the war-tki'ie he has been resident in the Nanking Museum, China, whe:･e he w.:`s 2ppointed Chief Researcher in 1942, and after the war his property was taken over by the hostile government). Since he repatriated in in 1946, Japan he has been compelled to collect specimens ; nd literature newly, and though they wei'e fairl> :iL]unclantly collected they did not attuin the !'cz,rmer level, especially he ccuitd nott get rare speclmens agaln. ' In order to promote our knowledge of Japanese Po]yplacophox"a, I think it necessary to review the known species re$pectively. In this short note is dealt with a common spccies of Ischnochiton in Japan.

The status of Ischnochiten coinPtzts and I. boftin･Efsssg's

The specific identification of the most common species of ib('lt?torthiton in the rocky shore of Japan has been not quite easyv ; Isao li-nki (1924) showed it undeterminedin his first paper. But later he identii''/ed it with L co7nPtzfis Gould, which was unfigured in Pilsbry's description in Manual of Conchology In 1933 (1892). Bergenhayn described L bofr･iitensi･; as a new species from Misaki, Kanagawa Prefecture, Shimonoseki and Chichi- jima in Bonin Islands, but not compare did it with t. co7nPtifs, apparently unaware of the presence of that species. In tlie same year I'$zo Taki annottnced and reviewed BergenhaynLs paper, saying that bonntefz,sis-- thaanit?#..,i '.conzPtzes. Dall, ]926, and iebrifzzts However, he later (1938, p. 3S9,/ discriminated two species [)s follows; e: upon examination of nurnerous specimens collected froin the t:Nrpe locali- ty and from other places of Japan, I can clear.ly distinguish two forms, one of which has smooth and the other distinctly striated scttles, both occurring :tn almost always the same habitat. I do not, therefore, hesitate to consider the specimens of smooth scales as L eomPtzfs and that of striated scaies as boninensis L of BergenhaynQ933)." Also he ･ibid., p. 370) treated thaanztmi -- comPtzvs. His view was clearly m.etnir'ested in his

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'' TAki:Chiton Fauna of Japan (1) 343 f

"D6butsu-Zukan" figures and descriptions in (Encyc]. Fauna Jap, an) (1947)

in which he discrirninated these two .species as distinct, with the follow-

ing characters:

L comPtzts (Gould) (Usu-hizara-gai). ... Girdle scale larger and less in

number, its surface smooth; outline of animal short and wide;

posterior area of tail valve narrower; distribution-from Honsha

. to Philippines and Outer South Sea Islands.

f. bofzinensis Bergenhayn (Hoso-usu-hizara-gai).. . . Girdle scale smaller

and provided with 12-15 shallow grooves; di$tribution-･from

HonshU to South China.

In so far as the surface sculpture of girdle scales is conce'rned, his

treatment is inappropriate, because though he says that in comPtzas the

scales are smooth, they are grooved in the original description. namely:

``Girdle rLPilsbfy, narrow, imbricated vvith small elongated grooved scales'';

"....sca]es, 1892, p.117). Also Carpenter"s description (ibid.) runs some-

times very slightly striated..... the striulation of the scales can seldom

" be seen. ...

Nierstrasz (1905) figured and described I. comPtus (p. 24, pl. 1, fig. 10)

but the outline of the animal js considerably oval, which is narrow ante-

riorly arid very wide posteriorly. Though the out!ine of the animal is

subjected to a wide range of variation I have never met with such a wide

specirnen, at least frem Japanese localities. He does not explain the surface

of the girdle scale, but it seems to be smooth judging from his figure

(pl. 3, fig. 84). The identification of this species seems to need further

examination.

When Bergenhayn i (1933) described bonineitsis as a new species, he

compared it with longiaymba, which occurs in New Zealand, so that his

comparison is out of the focus from the view-point of locality. Moreover

the name longiaymba Quoy & Gaimard is preoccupied and should be called

maorinus Iredale,1914. IIis description of beninensis in the outline of

the animal, dimension, sculpture of shell-plates, their interior, gjrdle-scale

etc. well agrees with the characters ef comPtus. He says

"Dorsalschuppen ....haben eine glatte oder auch schwach gefurchte Dor-

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344 VENU.S..: 22 (4) 1964

salseite,:' but the scale shown on his Text-fig. 3a is smooth; also he did

not describe the number of shallow grooves. In the figure of the radula (Text-fig. 3e) he failed to show the basal part of the first lateral tooth

(cf. Is. Taki, 1938, pl.27, fig. 6) and the･ stem of the second lateral seems

too slender judged from my observation on the material of comPt"s at

hand and the position of the inner wing seems inappropriate. As a whole

his figures of the radula seem somewhat inaccurate. In conclusion, I think

think that boninenSis is a synonyrn of eomPtnts.

Isao Taki (1938) described comPtzts in detail based on material from

Mutsu Bay, with notes on the known localities and distribution. It was

followed by the description of L Paztlitlzgs, n. sp., with remarks on the relation to melinvas, mitsz-eleztrii and boninensis, all ef them previously known frorn Japan. In this paper his view to place comPtzes and bofzinensis'

collaterally is well shown, and the same treatment is seen in all his later

works (1947, 1950, 1954, 1960. 1962), followed by many authors of icono- graphs and catalogues of Japan.

Leloup (1941) deScribed I. comPtzvs based on specimens from Misaki,

in his paper on Ischnochiton species frem Tsingtao, China; concerning

"les the girdle sca}e he says that jeunes 6cailles pr6sentent des c6t6s longitudi'nales bien marqu6es," and also gives some comments on thaanztmi

and boninensis, that both of them are closely allied to comPtzfs, but

witheut any decision about the specific distinction of these species from comPtz-s.

I have been somewhat sceptical about Isao Taki's treatment on the

above species since 1933, because;

(1) While the outline of the shell-plates in comPtigs is ellipsoid and in boninensis elongate ellipsoid, this character is not constant and it is

nearly impossible to distinguish comPtzfs of elongate shell-plates from

boninensis of short shell-plates. The sculpture of shell-plates is also quite

variable and cannot be a proper criterion of discrimination.

(2) He says that posterior area of the tail-valve is wider in boni-

nensis while it is narrower in cemPtus, but this distinction is not so

clear-cut among numerous specimens.

(3> These two species cannot be discriminated by the form of the

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TAKI:ChitonFaunaof Japan (1) 345

t ttt tt / ,.. 't/' -,:',"i ttttt i. /.--,,'Ll- /' .lt/1('-' /1',1 L;'I,Itlll'f,,.,1' ,,･ ･ g.1.,,/-i,,g.･,-1,･ -l-l,',,,lt,{ ,. -, 1.1.ll, .-, Z･･ -'"T.'','t tE }i.'i･--.'-. t-･{'. t... .,. i,,/-,',i?,･-/･.',･-;t-;-,ttt,,.･.S///L,',

rw-

.M t.!., twes '1･rv. ',i'-' it' ', e.;it.･.X. - ･..,ag :-.t;II;. ifl- tt,t'･ tt･iifl.rtt'/, .L･-fX･t

Text-figs. Dorsal views of (1) Ischnochiton comPt"s f. comPtus s.str. Length ef largest specimen, 24mm. Loc. Mitsune-mura, Hachij6 Island;

(2) L comPtus f.isaoi, form. nov. 23.8mm. Loc. Hayarna. Kanagawa Pref.

radula.

(4) The range of distribution of these two species agrees with the

exception in the northern and southern regions. In Honsha and Shikoku

at least, the locality does not differ vertically, nay these two species were

collected at the same spot, so that it is probable that these two live in the

same ecological niche.

Iagree with Isao Taki that these two may be treated as somewhat

different, as no intermediate forms has been found thus far, but by the reasons above given it is dithcult to take these two as a distinct speeies or even a subspecies, and I propose that they should be treated

as forms of one species comPtzvs, namely one form may be called comPtus

s. str. which was identified as comPtzas by Isao Taki with a slight modi-

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346 VENUS:22 (4)1964

!

Arrangement of girdle scales on the right side of intermediate

valves ef (3) L eomPtus f. comptus; (4> L comPtus f. isaoi. × ca.

30; Detached scale of (5) L comPtus f. comPtus; (6) L comPtus

f. isaoi. × ca. 90. a, striation conspicuous; b, striation nearly obsolete.

fication of characters given in the original description, and the other isaoi,

form. nov. which was identified as boninensis by Isao Taki, the name of'

which was lost by synonymy with comPtus.

Concerning geographica! distribution, it is generally known that two

closely-allied species or subspecies of animals do not inhabit the same

locality and there is seen the segregation of habitat (Miyadi & Mori, 1953),

though sometimes the range of the two habitats partly overlap, and also

if both live in the same habitat, they occur in different ecological niches.

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TAKi : ChLLtLe..p...E.q.vpa of Japq.p."g) 347

i L comPtus L comPtus Item (Text- i (Text- forma cumPtus (s. str.) forma isaoi,f' nOV. fig.> l fig.) i Outline of body ellipsoid or elongate elongate ellipsoid or [IL l [2] and she!i-plates ellipsoid lellipsoid

Size larger (width ca.340,"} 15I smaller (width ca.270u) [6]

Girdle- No. scale less numerous (ca.12) l3i more nuinerous (ca.16) [4] in radial scale lineSurface

smooth tL5[ with 12 18 very shallow [6] grooves Gegraphical 1 From Hakodate to Australia From Misaki to Ryukyu distribution

Of coursc herewith we can remembor the presence of Jordan's rulei). In

this case it seems nearly impossible to distinguish one habitat from

another, and I think that, if the distinction exists at all, it may be far

below thc subspecies level.

Ischnochilon (Isch7zochiton) comPtvfis

Chito･n (LePtvchiton) comPtus Gould, 1859, p. 163; 1859a, p.117.

Ischnochiton (Ischnochiton) comPtus Pilsbry, 1892, p.117; 1898, p.51; (?)

Nierstrasz, 1905, p.24-27, 109---110, pl. L fig.10, pL3, figs.77---85.

Isehnochiton sp. Is. Taki, 1924, p.284, fig.

Ischnochiton thaanumi Dall, 1926, p.66.

Ischnochiton (Ischnochiton) boninensis Bergenhayn, 1933, p.10-13, pL1, fig.2 3,

pl.2, fig.24-29, 32, text-fig.3. (cf.Is. Taki, 1933, p.193)

Ischnochiton (Ischnochiton) comPtus Is. Taki, 1938, p.366-371, pl.14, fig.5, 10, --16, -16 pL 15, fig. 6-7, pL 25, fig. 9-- pl. 27, fig. 6-7, pL 29. fig. 11 ;

Leloup, 1941, p.8-21, pLl, fig.2, text-fig.4;

Is. Taki, 1947, p.1267, fig.36e2; Is. Taki & Iw. Taki, 1950. p.123;

Kira, 1959, p.183, pL67, fig.1; Is. Taki, 1960, p.197, pL90, fig.6.

Locality: Hakodate, Hokkaido; Hachij6 Island; Misaki, Kanagawa Pref.;

Kushimoto, Wakayama Pref.; Shikoku; Kyitshit; Ryakyit; Southern coast

of Korea; Formosa; Tsingtao, China (Leloup, 1941); Philippines; Indo-

1) If we take a given species in a specified area as a starting point, we de not find its nearest relative in the.same district, nor in a dlstant one, but in adjacent area separated by some barrier (Hesse-Allee, 1937, p.75).

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348 VENUS ： 22 （4） 1964

nesia ？ Nierstrasz 1905 （） （ ， ）； Australia （Leloup ， 1941 ）．

Ischnoc 〃iton 1so伽 oo 痂 げo π comPtzts Gould 1859 f6rma ゴs α o ゴ n ． （ ） （ ， ） ， form ．

Chiton Lepto ‘ 配 彦o com t” s （ の ψ Gould ， 1859 ， p ．163 （partim ）．

1schnochiton boninensis Bergenhayn ユ933 ．10 − ， ， p 13 （partim ）．

13 ‘ hnochiton boninensis ， non ． ． Is Taki ， 1947 （ Bergenhayn ）， p 1267 ， fig 3601 ；

Is． Taki ＆ Iw ． Taki 1950 。123 ， ， p ； S ．Hirase ， 1951， pl ．55 ， fig．1 ；

Utinomi ， 1956 ， pl．47 ， 負g ．6 ； Baba ， 1958 ， pl．75 ， fig．；

Kira 1959 183 67 行 ．2 Is． Taki 197 ， ， pL ， pL ， g ； ， 1960 ， p ． ， pl ．90 ， fig．5．

Locality ： Misakl Kanagawa Pref ． Izu − aud ， ； It5 Izu Shichit6， Shizuoka ． ＝ Pref ； Ogasawara Islands （ Bonin Is．）； Kushimoto ， Wakayama Pref ．；

Shikoku Chekiang and Fukien China ． ； ，

Summary

1． Ischnocltiton boninensis Bergenhayn − ， 1933 should be taken as a syno

nym of I．co77zptzts （Gould ， 1859 ）．

2。 Aspecies which has been called 1． bofzinensis by Isao Taki （1938 and ． ， ・ later can not be as species ） treated level， but a form of com 砂 tas （Gould ）

which may be called ゴsaoi for 皿 ， a nova ． ・ 滝 庸 （1938） は 日本 産 の ウ ス ピ ザ ラ ガ イ を Ischnochiton comptus （Gould ） と 同定

た が の し ， そ 時 に 肉 帶 上 の 鱗 片 表 面 に 条 線 の あ る も の と な い も の が あ り ， 表 面 平 滑 の も の

を comptus と し．条線 の あ る も の は 動 物 体 もい く らか 細 長 い の で 」， boninensis Bergen ・

hayn ホ ソ ウ ス ピ ザ ラ ガ イ と い う 別 種 と し て 区 別 し た ． こ の 両 者 は 最 も普 通 な ピ ザ ラ ガ イ

で 類 我 国 各地 に 広 く分 布 し て い る が ， そ の 産 地 も ほ と ん ど 同 じ で 更 に 生 態 的 地 位 （棲 息、 し

て い る 部 位 ） も 同 じ と 思 わ れ ， こ の よ うに 種 と し て 区 別 す る こ と は 困 難 な よ うに 私 に は 思

わ れ た ． LcomPtus の 原 記 載 に よ る と 鱗 片 は 溝 あ り と 記 さ れ て お り， 又 boninensis の 鱗 ． ． 片 も 1え滑 か 浅 い 溝 あ り と 記 さ れ て い る の で 庸 の 取 扱 い は 原 記 載 に 完 全 に は ．合 致 し な い も の ． で あ つ た ． そ れ で 私 は boninens is は comPtus の 異 名 と す べ き も の と 思 う ． こ の 両 者 は

・ の ・ 外 形 殻 板 彫 刻 歯 舌 の 形 態 で 厳 密 に は 区 別 で き な い が 中 間 型 も見 られ な い の で ， 私 は 一 comPtus ス 両 者 を 同 種 の 亜 種 よ り も下 の 階 級 で 品 種 と して 取 扱 い ， ウ ピ ザ ラ ガ イ forma ． COmPtus s ． str ． ・ は 外 形 が 楕 円 形 （又 は 長 楕 円 形 ）， 鱗 片 が 比 較 的 大 形 で 数 少 く表 面 平 滑 な

も の と し， ホ ソ ウ ス ピ ザ ラ ガ イ は boninensis と い う名 が 異 名 に な っ て 使 用 で きな い の で

forma isaoi， forma nova の ．新 名 を 設 け ， 外 形 が 長 楕 円 形 （又 は 楕 円 形 ） で 鱗 片 が 比 較

的 小 形 で 数 多 く表 面 に 条 線 が あ る も の と し た い ． 」 References

animals and Baba ， K ． 1958． Ecological photographs of Japanese littoral plants ．

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TAKI:Chiton Fauna of Japan (1) 349

Hokuryukan, Tokyo. (In Japanese)

Bergenhayn, J.R.M. 1933. Die Loricaten vQn Prof. Dr. S{xten Bocks Expedition

nach Japan und den Bonin-Inseln 1914. Kungl. Svensk. Vet. Akad. Handl., 12: 1-58, pls.1-3.

Dall, W.H. 1926. New shells from Japan and the Loochoo Islands. Proc. Biol.

Soc. Washington, 39: 63-66.

Gould, A.A. 1859. Shells of the Nerth Pacific Exploring Expedition. Proc. Boston

Soc. Nat. Hist., 7: 163.

1859. 0tia Conchologica, p.117.

Hesse, R. (transl. W. C. Allee & K. P. Schmidt) 1937. Ecological animal geography.

J. Wiley & Sons, New York.

Hirase, S. 195Z. A handbook of illustraterf shells in natural colors from Japanese

and adjacent territories. Bunky6ku, Tokyo.

Kira, T. 1951. Coloured illustrations af the she!!s of Japan. Hoikusha, Osaka.

Leloup, E. 1941. Quatre Ischnoch･itons de Tsingtao(Chine). Bull. Mus. Roy. Hist.

Nat. Belg. 17 (18): 1 15, pls.1-2.

Miyadi, D. & Mori, S,1953. Animal ecology. Iwanami, Tokyo. (In Japanese)

Nierstrasz, H.F. 1905. Die Chitonen der Siboga-Expedition. Siboga-Expeditie,

Monogr. 48, Livr. 20. Leiden.

Pilsbry, H. A. 1892. Monograph of Polyplacophora. Manual of Conchology, vol. 14. --･--- 1895. Catalegue of the marine Mollusks of Japan. Detroit.

Taki, Isao. 1924. Chitons found on the rocky shores of Misaki. Zool. Mag.

Tokyo, 38: 281-291. (In Japanese) 1933. Abstract and review of Bergenhayn's paper, 1933. Venus, 4 (3):

192--196. (In Japanese) ･- 1938. Report of the biolegical survey of Mutsu Bay (31). Studies on Chitons of Mutsu Bay with general discussions on Chitons of Japan. Sci. Reports T6hoku Imp. Univ., 4th ser. BioL, 12: 323-423, pls.14 34. --- 1947. Figures and descriptions of Japanese Chitons, in Illustr. Encycl.

Fauna Japan, rev. ed., pp.1265-1269, figs.3594-3608. Hokuryilkan, Tokyo.

(In Japanese)

1954. Polyplacophora from Japanese Islands. Gloria Maris (Minutes of

Tokyo Branch of the Malac. Soc. Japan), spec.issue, 1: 1-13 (mimeogr.)

1960. Polyplacophora,in Y. Okada et al. (ed.) Encycl. Zeologica Illustr.

in Colours, vol.3, p.197-200, pls.90-91. (In Japanese) ------1962. A list ef the Polyplacophora from Japanese Islands and vicinity.

Venus, 22 (1): 29-53. (Posthumu$ werk)

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350 VENUS ： 22 （4） 1964

＆ ． ． of of ． Taki ， Iwao 1950 A list Polyplacophora Wakayama Prefecture

Nanki Seibutsu ， 1 （3 ）： 122 126 ． （In Japanese ； mimeogr ．）

− Taki ， Iwao ． 1962 ， Rcminiscence of my brother Isao Taki his life and work ．

， 1 ： 13 28 1 ． in with English 加 ary Venus 22 〈 ） ， pL 〔 Japanese Sum ）

Utinomi ， H ． 1956． Colo 肛 ed illustrations of seashore animals of Japan．1｛Qikusha ， Osaka ． （ln Japanese）

ア フ リ カ オ キ ナ エ ビ ス の 歯 舌 に つ い て

東 正 雄

on of Notes the Radula Perotrochus africanus （Tomlin ， 1948 ）

Masao AZUMA

（挿 図 Text −fig。 1）

南 阿 Transvaal の Mrs ． Helen Boswell か ら ア フ リカ オ キ ナ エ ビ ス の 乾 肉 票 本 の 御

1963 恵 与 に よ っ て ， そ の 歯 舌 の 大 要 を 報 告 す る ． 本 研 究 の 進 行 中 ， K ．H ．Barnard （ ） の

報 告 が 公 け に さ れ た の で こ こ に 粗 訳 す る と 次 の よ うで あ る ．

“ ’ ． 中 歯 は 1 ； 側 歯 4 は 中歯 の 横 に 並 ぶ ； 更 に 多 く の 側 歯 の 最 初 は 短 く， 次 第 に 大 き く 25

つ 々 を 数 え る ， づ い て 徐 に 強 く長 く鎌 状 歯 尖 （falcate plate ） と な る も の 12 を 数 え る ． こ フ サ れ ら は 次 第 に 縁 歯 と な り 211瀰尖 と 房 状 毛 （tuft of bristle） が あ る も の 50 を 数 え る ． 最 外

． ” 側 の 縁 歯 の 6 は 細 長 い 板 状 ． そ し て 彼 は 歯 舌 式 を 1 ＋ 4 ＋ 25 ＋ 12 ÷ 50 ＋ 6 と 提 案 し た ． 私 ． は 1 個 体 の 歯 舌 リ ボ ン の 略 rl映 部 の 観 察 か ら 次 の 如 く記 述 す る ．

・ ． 3 1 1 2 中央 歯 は 細 長 く略 紡 錘 形 ， 側 崗 の 対 は 前 者 よ り大 形 ， 第 第 ， 側 歯 の 先 端 は 微 歯 尖 と

な る ． 第 3 側 歯 は 基 部 細 い が 次 第 に 広 くな り ， 先 端 大 き く歯 尖 を 旱 し て い る ． 策 1 内 縁 歯 ． 〜 t 2 〜 は 先 端 微 歯 尖 と な る ． 第 2 18 （内外 ）迄 は 非 常 に 短 く側 歯 の ／2 内 外 の 大 き さ ， 第 7 〜 ． 内 縁 歯 は 微 小 舟 型 ， 第 8 以 下 は そ の 尖 端 に1 微 歯 尖 が あ る ． 第 19 25 は 次 第 に 長 く延 び そ の 先 端 も歯 尖 が 次 第 に 大 き く延 び る ．以 ドは 外 縁 歯 と して 取 扱 う が そ の 区 切 り は 明 暸 で な い ． ’ 外 縁 歯 の 最 初 は 細 長 く先 端 鎌 状 に 曲 り微 歯 尖 と な る ． 次 に 房 状 毛 を 鎌 状 歯 尖 に 有 して い る

も の 多 い ． （是 等 は 此 属 の 特 質 で あ る ．） 最 外 側 ．数 個 は 細 長 い 惻 丿こ歯 尖 で 無 鈎 歯 で あ る ．

ヒ述 K ．H ． Barnard も Mrs ． H ． Boswell か ら 21 固体 の 材 料 の 剖 見 結 果 で

あ る ． 筆 者 は 1f 同休 で South Zululand 沖 160 〜 180 fms ． の 深 度 か ら 採 集 さ れ た も の で ， ．多 分 此 3 個 体 は 略 々 岡 じ 海 域 の 同 じ 深 度 に 棲 息 し て い た も の と 考 察 す る ．

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