• The Korean Journal of Zoology
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• v.39 no.2
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• pp.139-146
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• 1996

A studv on the ultrastructural changes of the hermaprodite duct epithelium in spring and summer specimens of a Korean slug Incirovia fruhstorferi was conducted. In spring specimen, the hermaphrodite duct was 0.3 H 0.2 mm in diameter and seemed to be a little bit abnormal feature, due to shrinkage. The epithelium of the duct was composed of cells containing various-sized vacuoles and their cytoplasm showed high electron density. In summer specimen, the hermaphrodite duct was 0.4 $\times$ 0.23 mm in diameter and seemed to be more voluminous than that of the spring specimen. The lumen of the duct in the summer specimen was lined by a epithelium composed of several cell types such as ciliated cuboidal, pseudostratified cuboidal, ciliated columnar and irregular cells. Phasocvtotic activities of the duct epithelium are observed only in the summer specimen. Both of the duct epithelia in the spring and summer specimens were surrounded by connective tissues at their bases. The results obtained suggest that the duct epithelia of the slugs experience seasonal variation in relation to their reproductive cycles.