SYSTEMATIC STUDIES ON THALASSINIDEA -I. LAOMEDIA ASTACINA DE HAAN-

Abstract

There exist a few incomplete descriptions about the structure of Laomedia astacina DEHAAN, but their details and further investigations have not yet been done. DE HAAN (1841, '49) paid a noticeable attention to the structure of his material Laomedia, in addition to the gill formula and its number, and the estimation thirteen in number. Following him, ORTMANN (1892) reported fourteen gills on his material from Tokyo Bay, though it was a little broken unfortunately. The problems on the gill formula of gnathobranchs and its number have been uncertain, while they had decided on the other two genera, Jaxea and Naushonia (GURNEY, 1942). I've speculated about the epipodites summed up by GURNEY (1942), but in this report I've accounted for the structure of gills and other parts, using the materials deposited in our Laboratory. Here I wish to express my thanks to Professor Sadayoshi MIYAKE for suggesting this investigation as well as for constant guidance in the course of the work.