著者
岡野 元哉 和田 年史
出版者
日本貝類学会
雑誌
Venus (Journal of the Malacological Society of Japan) (ISSN:13482955)
巻号頁・発行日
vol.70, no.1-4, pp.58-62, 2012-07-31 (Released:2016-05-31)
参考文献数
21

We investigated size structure and reproduction of violet shell Janthina prolongata stranded on the coast of Iwami-cho in eastern part of Tottori Prefecture, southwestern Sea of Japan, on 27 September, 2010. Shell length (SL) exhibited a bimodal size distribution with a range of 6.08–40.36 mm. Our results also indicated that individuals of more than 27.4 mm SL laid egg capsules under their bubble raft. Moreover, there was a significant positive correlation between the length of egg capsules and SL. Larger individuals had shrunken and differently colored egg capsules on the forefront of bubble raft, suggesting that J. prolongata might lay egg capsules intermittently.
著者
黒田 徳米
出版者
日本貝類学会
雑誌
ヴヰナス
巻号頁・発行日
vol.6, no.2, pp.81-84, 1936-06-20
著者
浜田 隆士 奥谷 喬司 棚部 一成 出口 吉昭 福田 芳生 波部 忠重 平野 弘道 蟹江 康光 川本 信之 三上 進 小畠 郁生
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.3, pp.131-136, 1978

Progress and some results of the second rearing experiment of Nautilus macromphalus in Tokyo are described. The temperature controlling experiment is still applying to three extant individuals, that were supplied from New Caledonia last year through the courtesy of the ORSTOM in Noumea, and they are surviving for 222 days in captivity (May 14, 1978). Copulating behaviors are observed mostly in the waters of 17-19℃ in temperature but not in the cooler conditions. Shell growth at the apertural periphery was first measured to find that some individuals probably in a gerontic stage show no remarkable increment on one hand, the young specimens show 10-12 mm elongation per 100 days on the other. Recently the JECOLN also takes care of a living Nautilus pompilius that had been floated possibly from the Philippines along the Kuroshio Current over 2, 000 km and was captured by a fishing net set off Kawajiri, Kagoshima Prefecture in Kyushu, Southwest Japan.
著者
幡野 真隆 石崎 大介
出版者
日本貝類学会
雑誌
Venus (Journal of the Malacological Society of Japan) (ISSN:13482955)
巻号頁・発行日
vol.74, no.3-4, pp.99-104, 2016-11-17 (Released:2016-12-10)
参考文献数
20

Feeding experiments on juveniles of the freshwater pearl mussel Hyriopsis schlegeli were conducted using upwelling chambers. Growth of juveniles mainly fed with a mixture of two green algae, Chlorella homosphaera and C. vulgaris, in 2013, was compared with that of specimens fed only with C. vulgaris in 2012. Juveniles in 2013 grew much faster than those in 2012 and their mean shell length exceeded 20 mm, achieving record maximum size. The result implied that using upwelling chambers and feeding small green algae are effective for successful culture of H. schlegeli.
著者
紀平 肇 近藤 高貴
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.58, no.3, pp.145-149, 1999
参考文献数
7

The age composition of 101 individuals of Oguranodonta ogurae, which were collected in a small pond at Hirakata City, Osaka Prefecture in the late autumn of 1998, was determined by examination of the annual gorwth-interruption lines. Individuals with 5 growth-interruption lines (i. e. 6 years old) were most abundant, and there were only 5 individuals younger than 5 years old. The scarcity of young individuals may be due to the heavy drought occurred in the summer of 1994. Based on the assumption of the stable age distribution, a life table was estimated. The estimated generation time was 6.3 years.
著者
坪川 涼子 ウィラン リチャード C. 奥谷 喬司
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.4, pp.249-263, 1992

従来日本産Pleurobranchaea属としてはウミフクロウにP. novaezealandiae Cheeseman 1878が, ツノウミフクロウにP. sp.の学名があてられていたが, それらの学名について検討した結果, 前者にはP. japonica Thiele, 1925, 後者にはP. brockii Bergh, 1897の学名をあてるのが最も適当であることがわかった。ウミフクロウに以前にあてられていた学名P. novaezealandiaeは, 現在ではP. maculataとシノニムとされている。P. japonicaは神戸産の標本をもとに記載されたが, 腹足, 背楯, 歯舌, 顎板などの形態のみの不十分な記載であったために, P. maculataとシノニムである可能性が疑われていた。本研究によりP. japonicaはP. novaezealandiae=P. maculataとは外部生殖器官の位置や形態, 腹足腹面の色, 幼生の殻の形態と浮遊期間に明瞭な相違があるため, 独立の別種であることがわかった。ツノウミフクロウについては, Baba (1949, 1969)によりPleurobranchaea sp.として記録されていたが, 本研究で腹足背面の突起, 頭膜前縁の小突起の列, 内部及び外部生殖器官の特徴により従来インドネシア海域とアフリカ東岸から知られていたP. brockiiであると結論された。
著者
蟹江 康光 服部 陸男 中山 英明 関 邦博 水嶋 康男 設楽 文朗 伊藤 信夫
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.40, no.2, pp.86-94, 1981-07-15 (Released:2018-01-31)

In a hyperbaric chamber, living mature specimens of Nautilus pompilius withstood the hydrostatic pressure of 8.31 MPa (84.7 kg/cm^2) equipvalent to 827 m-depth in the sea and 7.89 MPa (80.5 kg/cm^2) equivalent to 785 m-depth, respectively, before it was killed instantly by implosion, the animals reacted physiologically to increasing pressure including increased partial pressure of oxygen with the compression rate (0.0981 MPa/min). This suggests that Nautilus undergoes severe stress during rapid descent and ascent through the water column. The shell implosion was caused by maximum strain-shortening (1.3% of the length). The shell implosion under pressure seems to have occurred at an old air chamber or siphuncular tube but not at the last septum of the phragmocone. Consequently, the depth of approximately 800 m is considered to be the maximal depth that N. pompilius is durable. The result will be usable for interpretations on paleobiology of extinct nautiloids and ammonoids which have similar shells and siphuncular tube system as living Nautilus.
著者
速水 格
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.41, no.3, pp.233-236, 1982-10-31 (Released:2018-01-31)

Cryptopecten is well characterized and clearly distinguishable from Aequipecten and other pectinid genera by the highly allometric growth, Campto-nectes-like sculpture in early growth stages and regular persistent radial ribs as well as the development of numerous imbricated scales covering the sides of each radial rib with some hollow space. The following recent and fossil species are confirmed as the constituent species of this genus. Cryptopecten alli Dall, Bartsch and Rehder, 1938 ; Hawaii, Philippines, South China Sea and southwest Japan ; Late Pliocene to Recent. [All the specimens hitherto referred to Pecten tissotii by Japanese authors belong to this species.] Pecten nux Reeve, 1865 ; Polynesia, Melanesia, Philippines, Formosa and southwest Japan ; Middle Pliocene to Recent. Pecten vesiculosus Dunker, 1877 ; central and southwest Japan ; Middle Pliocene to Recent. Pecten (Aequipecten?) yanagawaensis Nomura and Zinbo, 1936 ; north and central Japan ; Middle Miocene. Cryptopecten sp.; Japan (Kikai Island) ; Late Pleistocene.