On the Variation of Spines in the Japanese Top-Shell, Turbo cornulus SOLANDER
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概要
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There are two varieties of Turbo cornutus SOLANDER in the seas surrounding Japan: spined and spineless ones. The Japan Sea and the waters east to Kusimoto (Wakayama Prefecture) on the Pacific side offer the former while the majority of the top-shell found in the Inland Sea represent the latter. Kii Channel, which connects waters of the Pacific and the Inland Sea, provides a living, place for more spined top-shells than the Inland Sea and their percentage increases as we go down the channel to the south. Approximately 50% of the top-shells have spines which are found on the coast of Tosa. Three types of spined top-shells may be recognized: A, B and C where all top-shells are spined, the majority of the shells are referable to type A, type C being rarest. Where spineless top-shells are abundant, type C leads the list; next comes type B, and most scarcely occurs type A. Significant correlation is seen between the length of the shell and the number of the spines, the larger the shell the more numerous the spines. Those found in the Japan Sea have many spines and those in the Pacific Ocean have few. Careful observations have led to the conclusion that the correlation between the length of the shell and the number of spines is nearly the same in value among those found in Uradomi (Tottori Prefecture), Yobuko (Saga Prefecture), Siganosima (Hukuoka Prefecture), Turuga (Hukui Prefecture), Takeno (Kyôto Prefecture) and Kasumi (Hyogo Prefecture), but those found in Hagi (Yamaguti Prefecture), Simoda (Sizuoka Prefecture), Saisyuto (Tyosen), Kusimoto (Wakayama Prefecture), Dozen, Oki Islands (Simane Prefecture), Izima (Tokusima Prefecture) and Hunakosi (Miye Prefecture), display respectively their local characteristics, no intermingling being detected among these districts.
- 社団法人 日本水産学会の論文