著者

伊藤 泰弘

出版者

JAPANESE ASSOCIATION OF BENTHOLOGY

雑誌

日本ベントス学会誌 (ISSN:02894548)

巻号頁・発行日

vol.1994, no.47, pp.23-36, 1994-08-30 (Released:2009-08-07)

参考文献数

25

被引用文献数

1 1

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Two discrete morphological types were recognized among the populations of a boring bivalve, Penitella kamakurensis, based mainly on whether the anterior end of the shell (beak) is pointed (P-type) or rounded (R-type). The relative abundance of the two types varies from place to place according to the hardness of the rock in each locality. P-type individuals are abundant in softer rocks and R-type in harder rocks. In R-type individuals, the width of growth band is narrower, the size of posterior adductor muscle scar is larger, and the shell is thicker than in P-type individuals from the same locality. Individuals of either shell type living in harder rocks show the same tendencies in comparison with those of the same shell type from softer rocks.