著者
大久保 修三 黒川 忠英 鈴木 徹 船越 将二 辻井 禎
出版者
日本貝類学会
雑誌
貝類学雑誌 (ISSN:00423580)
巻号頁・発行日
vol.56, no.3, pp.259-269, 1997-10-31 (Released:2018-01-31)
参考文献数
28

Generation of the streak-like flash in the inner-fold of the mantle in Ctenoides ales was investigated by video-camera recording, and stereo, light, fluorescence and electron microscopy. The stereo microscopy revealed the presence of a pale white band along the entire width of the marginal edge of the shell side surface of the inner fold. Since the flashing could not be seen in the dark, it was not due to the luminescence but the reflection of light. The light microscopy showed that the band region consisted of about ten rows of epithelial cells, cylindrical and 40 μm tall and 10 μm wide. The cytoplasm was densely filled with fine granules, eosinophilic in H-E staining. Under the electron microscope, those granules appeared as electron-dense vesicles, 0.5-0.6 μm in diameter, each containing a highly electron-dense spherical core, 0.2-0.3 μm in diameter. The cell had a nucleus, few mitochondria and lysosomes, however, other cellular organelles such as Golgi apparatus, rough and smooth endoplasmic reticulum were not evident, in the present observation. We assume that the electron-dense vesicles packed in the cytoplasm function to reflect light strongly. This highly reflecting structure found in C. ales is quite different from those have been reported in eyes of scallop and squid, and in iridophores of giant clam, cuttlefish, long-spined sea urchin and of fishes. The video observation showed that the mantle made a movement to roll the white band towards the shell-side and then, within a second, the rolling movement was released. The phase of the movement was different by the portions of the mantle, and the mantle edge made a wave-like motion. When the pale white band was hidden by the roll, the reflection of light disappeared. When the rolling was released, the reflection of light reappeared. Since the "roll and release movement" repeat quickly, it looks as though a streak-like flash run along the mantle margin.
著者
浜田 隆士
出版者
日本貝類学会
雑誌
貝類学雑誌 (ISSN:00423580)
巻号頁・発行日
vol.24, no.3, pp.181-_198-1_, 1965-12-30 (Released:2018-01-31)

Post-mortem drift of the Recent Nautilus shells by oceanic currents is exemplified by the materials collected from the west coast of the Malayan Peninsula and the Japanese Island arcs. Characteristics of habitat (H) and realm of post-mortem transport (T) in general fossil assemblages were schematically explained. T is composed of H, To and Tt, where To is the realm of postmortem transportation outer than H in usual condition, and Tt is the extended portion of To especially caused by an oriented agency of transportation such as turbidity current or strong oceanic current for instance. Thanathocoenose in H is tentatively called as quasiautochthonous assemblage being separated from the true autochthonous, i.e. orthoautochthonous one. Thus, allochthonous assemblage is defined as the dead assemblage out of H or the inner realm of post-mortem transportation. In short, there is an almost fixed relationship between H and T insofar as the areal distribution, and an inequality T>>H, where T=H+To+Tt, is given. The distributional pattern of T inclusive of To and Tt is also diagrammatically presented. Its general figure shows an asymmetry to the center of H. State of preservation, density of distribution and other g neral characteristics of a thanathocoenose should have a tendency to decrease as the realm becomes wider and wider. This tendency is named H→Tt declination.
著者
林 一正 大谷 章栄
出版者
日本貝類学会
雑誌
貝類学雑誌 (ISSN:00423580)
巻号頁・発行日
vol.26, no.1, pp.17-28, 1967-09-10 (Released:2018-01-31)
被引用文献数
1

セタシジミの消化管内容物を4月, 8月, 10月, 12月の4季節について検鏡して次の諸結果を得た。1. 消化管内容物は4, 8月の材料では消化管内1/3以上つまっていたが, 10月分には殆んど見られず12月分にはまた多量に入っていた。2. 乾燥重量%で消化管内容物の約37%が有機物であった。3. 面積比で消化管内容物の62∿70%が腐植物と泥土類, 2∿3%が淡水海綿の骨針, 残り29∿36%が動・植物であった。4. 消化管内容物より硅藻類23属89種39変種3品種;緑藻類6属12種1変種;鼓藻類1属4種1変種;藍藻類10属14種2変種;輪虫類・原生動物3種;その他に淡水海綿の骨針, 腐植質等を検出した。5. 検出されたものとしては特に, 硅藻類, 鼓藻類が夥しく, 硅藻類ではStephanodiscus carconensis及びその変種とMelosiraが大部分で, 8月砂・砂泥地の材料で上記属合して50%前後の他は平均80%以上を占めており, 鼓藻類ではStaurastrum dorsidentiferum var. ornatumが10月に各底質の材料で, 12月に砂・砂泥地のもので50∿60%を占めている。6. 冬季摂食量は他の季節に比べて最も多いが, 消化の程度は低い。7. 季節による消化管内容物の差はあまりない。
著者
藤原 次男
出版者
日本貝類学会
雑誌
貝類学雑誌 (ISSN:00423580)
巻号頁・発行日
vol.37, no.1, pp.22-28, 1978 (Released:2018-01-31)
被引用文献数
1

Though gonad of Corbicula leana PRIME is in maturity all the year round, spawning takes place exclusively at the time when mean maximum water temperature for ten days is maintained more than 19℃. Even in the winter season, ovulation takes place if the minimal water temperature is kept above 19℃, and the spawned eggs grow up to D-shaped larvae. Therefore, this freshwater clam is productive all the year round if under a favorable temperature condition. Such a high temperature preference of this species suggests that Corbicula leana PRIME may be of tropical origin. Ovulating activity continues to few hours in the morning or in the evening. The temperature for the natural spawning varies by season, namely, 15℃-17℃ in April, while 18℃-22℃ during June to September. Maximal frequency of ovulation for a mother shell of shell length 25 mm has been six, and the mean for the whole population is two. The interval between successive ovulation is 103 days in maximum and 8 days in minimum. In the most case, it is about 30 days. Mother shell of shell length about 40 mm ovulates only once.
著者
木村 妙子 関口 秀夫
出版者
The Malacological Society of Japan
雑誌
貝類学雑誌 (ISSN:00423580)
巻号頁・発行日
vol.53, no.4, pp.307-318, 1994-12-31 (Released:2018-01-31)

ホトトギスガイMusculista senhousiaとコウロエンカワヒバリガイLimnoperna fortunei kikuchiiは, 静岡県西部に位置する浜名湖の奥部の潮間帯に優占するイガイ類である。筆者らはこれらの幼生を室内飼育し, 得られた試料をもとに2種のD型幼生から初期稚貝までの外部形態および交装を比較した。試料はSEMと光学顕微鏡を用いて観察した。その結果, D型幼生, 殻頂期幼生および初期稚貝のすべての成長段階で2種の間には, 形態に相違が認められた。D型幼生ではコウロエンカワヒバリガイの方がホトトギスガイよりも殻長が大きい傾向があったが, 計測値は重複しているので, D型幼生の種を殻長のみから同定することは困難である。しかし, D型幼生の交歯は, ホトトギスガイが14-15個であるのに対し, コウロエンカワヒバリガイでは9-11個と差異がみられた。殻頂期幼生では, ホトトギスガイの中央の交歯は小さくなり, 第1靱帯が交歯中央やや後方に形成される。殻の輪郭は卵型で, 殻頂は中央に位置する。これに対し, コウロエンカワヒバリガイでは, 殻頂期幼生の交歯は同大であり, 第1靱帯は交歯後端に形成される。殻の輪郭はほぼ三角形で, 殻頂は前方に偏る。初期稚貝では, ホトトギスガイは3種類の側歯を持つのに対し, コウロエンカワヒバリガイは側歯類を欠く。殻頂の位置は, コウロエンカワヒバリガイの方がホトトギスガイよりも前方に偏る。
著者
上島 励
出版者
The Malacological Society of Japan
雑誌
貝類学雑誌 (ISSN:00423580)
巻号頁・発行日
vol.54, no.3, pp.161-173, 1995-09-30 (Released:2018-01-31)
参考文献数
12

"Succinea" lyrata Gould, 1859 and "S". horticola Reinhardt, 1877 are common succineid species that are widely distributed in Japan. Recently, these succineids have been assigned to the genus Neosuccinea, although they lack vaginal appendix which is diagnostic feature of Neosuccinea. Shinagawa & Yano (1983) pointed out similarities in male genitalia between these problematic succineids and N. kofui which has prominent vaginal appendix and suggested their close relationships. Since the current assignment of these problematic succineids to Neosuccinea is dubious, re-examination of their taxonomic relationships with N. kofui has been needed. However, taxonomic position of these succineids remained unsolved, because N. kofui could not been rediscovered after the original description. The present paper reports a rediscovery of N. kofui after 24 years absence in formal records. Although N. kofui had been recorded from no other place than the type locality, Kofu, Yamanashi Pref., the present study revealed that this species is widely distributed in the Kanto district. N. kofui seems to have been misidentified as "S". horticola in previous records, due to their close conchological similarities. The genital morphologies of "S". lyrata, "S". horticola and N. kofui are redescribed to clarify their taxonomic relationships. By comparing the genitalia of "S". lyrata and "S". horticola, I found no significant differences that warrant taxonomic separation. Since they are identical in conchological and anatomical traits, especially in their unique internal structure of penis, "S". horticola is synonymized with "S". lyrata. On the other hand, "S". lyrata is highly divergent from N. kofui not only in the absence of vaginal appendix, but also in internal morphology of penial complex, mode of insertion of vas deferens to epiphallus, internal structure of lower oviduct, morphology of vas deferens and unique connection between vagina and retractor muscle. Since penial complex of N. kofui and "S". lyrata are substantially different in their internal structures, their similarity in male genitalia is now proved to be superficial resemblance and hence their close relationships are not supported. Considering taxonomic significance of vaginal appendix together with many structural differences in various genital organs, the current taxonomy of "S". lyrata placed in Neosuccinea was rejected. Alternative generic assignment of "S". lyrata to Novisuccinea was also rejected. The current results show that "S". lyrata belongs to the genus Succinea (sensu lato).
著者
ロドリゲス ロメロ F. ラガルダ フィゲラス A. ウリベ アルコセル M. ロハス ララ M. L.
出版者
日本貝類学会
雑誌
貝類学雑誌 (ISSN:00423580)
巻号頁・発行日
vol.38, no.3, pp.180-184, 1979
被引用文献数
3

アメリカガキCrassostrea virginicaの地方種群について, 染色体レベルでの比較検討の可能性をさぐる目的で"G"バンドパターンを調べた。メキシコ湾タバスコ地方のマンチョナ礁湖産アメリカガキの生殖巣から, エア・ドライ法(著者等1978)により染色体標本を作成し, BAKER等(1975)の簡易法で"G"バンドを観察した(第1図)。"G"バンドパターンは対合する染色体で完全に一致した。各染色体対ごとのバンド数は第1表に示すとおりであり, 各染色体のバンドバターンは第2図のようである。アメリカガキ地方種群の間には生理的変異のあることが知られているが(LOOSANOFF and NOMEJKO 1951, STAUBER 1947)そのような変異が染色体上に反映しているかどうか, 各地の種群についてこの方法で確めるのが今後の課題である。抄択 稲葉明彦
著者
波部 忠重
出版者
日本貝類学会
雑誌
貝類学雑誌 (ISSN:00423580)
巻号頁・発行日
vol.50, no.2, pp.95-97, 1991

A new species of the genus Zafra, Z. yukitai is distinguished from two other species, Z. divaricata Pilsbry and Z. albomarginata Okamoto & Habe in having much smaller shell ornamented with two white bands along the suture and on the periphery of the body whorl. These three species comprise a new subgenus Mokumea by peculiar ornamentation.
著者
奥谷 喬司 後藤 芳央
出版者
日本貝類学会
雑誌
貝類学雑誌Venus : the Japanese journal of malacology (ISSN:00423580)
巻号頁・発行日
vol.42, no.4, pp.305-311, 1983-12-31

北アメリカ大陸南東岸フロリダから, カリブ海, アンチルス列島を経て, 南米北東岸に分布するアダンソンオキナエビスガイEntemnotrochus adansonianaのうち, 隔絶した孤島バーミュダ沖から産出する個体群を別亜種と認めたのでここに記載する。新亜種バーミューダオキナエビスガイE. adansoniana bermudensisの多くの形態的特徴は基本亜種のそれと共通しているが, 次の諸点で区別し得る。(1)殻頂角が小さく(63°), 基本亜種のように螺塔は凸状の概形を示さず, 尖る。(2)切込みが短かく, 基本亜種では150°以上に及ぶが130°程度である。(3)殻の表面は基本亜種のように光沢がない。(4)調査標本は殻高55.5mm(完模式標本)ぐらいであるが, 軟体部が保存されていないのでこれで成熟個体か否か判断は出来ない。
著者
東 正雄
出版者
日本貝類学会
雑誌
貝類学雑誌 (ISSN:00423580)
巻号頁・発行日
vol.26, no.3, pp.74-77, 1968
被引用文献数
1
著者
加瀬 友喜 狩野 泰則
出版者
The Malacological Society of Japan
雑誌
貝類学雑誌 (ISSN:00423580)
巻号頁・発行日
vol.58, no.1, pp.1-8, 1999-03-31 (Released:2018-01-31)
参考文献数
15

A bizarre gastropod species, Pluviostilla palauensis from a shallow-water, submarine cave (gloomy to totally dark inside) in Palau is described as a new genus and species based on the empty shells. The species is small in size and has unique shell features such as an overall inverse raindrop-shape, architectonicoidean-like planispiral early teleoconch whorls, abapically projected tube-like aperture and hollowed umbilicus completely closed by the whorls. Shell wall microstructure and protoconch morphology suggest a possible affinity to neritopsines, but it is very tentative and the systematic position of this species is still unknown. A sedentary mode of life, as in architectonicoideans, is inferred for the species.
著者
藤田 敬 波部 忠重
出版者
日本貝類学会
雑誌
貝類学雑誌 (ISSN:00423580)
巻号頁・発行日
vol.50, no.1, pp.23-26, 1991

A valvatid snail found in the Lakes Kizaki and Nakatsuna, Nagano Prefecture, is the closest to Cincinna simusyuensis (Miyadi, 1935), but differs therefrom in having 60-65 ciliated growth lines. Thus, it is here described as a new species Cincinna kizakikoensis.