日本産普通多足類の後胚発生 : X ヤケヤスデの生活史

概要

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The life history of Oxidus gracilis was observed at Niihama district (Ehime Prefecture, Japan) during the year 1959 and 1961. The results were as follows: 1. The animals pass through seven larval stadia and sexual maturity occurs in the eighth stadium. Sex differentiation takes place in the larvae of the fourth stadium. Male animals develop a pair of very minute gonopod-bud appears at the position where the eighth legs had grown in the former stadia. The gonopod-bud scarcely grows during the stadia from the fifth to the seventh. However, it changes abruptly to a pair of complete gonopods at the eighth stadium. 2. The animals may be divided into two strains according to their breeding season. a) Strain breeding in Spring: The adults begin to crawl out of hibernation in early spring, and lay eggs from April to May. The larvae of this strain become adult at the end of November and then hibernate. b) Strain breeding in Autumn: The animals hibernate at various larval stadia as the fifth, the sixth or the seventh, and become mature in the early summer of the nest year, and lay eggs in autumn.
1962-08-15