巻貝類の天然餌料に關する研究(II)一鮑

概要

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The materials of the present study were collected in the summer of 1939 from the coast of Mie Prefecture, the well-known region for the most abundant production of Abalone in Japan. Brawn algae (Eisenia, Sargassum, Dietyota and Desmarestia, etc.) and eel grass (Phyllospadix) were again found in the digestive canals of Abalone, viz., Haliotis gigantea and its subspecies, H. giqantea sieboldi REEVE and H. gigantea discus REEVE, as already observed in those of Haliotis kamchatkana JONAS (Sea: UEDA and OKADA, this bulletin, Vol. 8, no. 1, 1939). To put more precisely, three species, namely, Desmarestia tabacoides OKAM., Dictyota sp., and Neurocarpus sp., were newly found by the present study whereas Desmarestia viridis LAMX. and Alaria sp., which were reported on in our previous paper, were found entirely wanting. Such a difference of foods appears to be due to that of localities of Abalones ince H. gigantea and its two subspecies collected from the same locality have the same food habit on the one hand, and H. kamchatkana obtained from quite different place shows a significant change in the contents of the digestive canals as compared with the former species and its subspecies, a fact pointing to a conclusion that the difference of distribution of algae is of prime impor ?? ance in determining the kinds of food taken by Abalone.