ON THE POLYP AND MEDUSA OF THE HYDROMEDUSA, GASTROBLASTA CHENGSHANENSIS LING

Abstract

Gastroblasta chengshanensis LING is a medusa belonging to the Leptomedusae, which is commonly found in Japan. This medusa is characterised by having more than one manubrium and multipling by fission (Figs. 6A and 6B). Concerning the mode of fission of this medusa, or those of other species of the same genus, there have been published several reports. In the present paper, the multiplication of medusae by fission, especially as it is affected by temperature, will be described, based on the occurrences of the medusae in the sea and experiments in the laboratory. In addition, some notes are given on the polyp of this medusa, which the author obtained from the planulae reared in the laboratory.