Studies on Ostracoda in Fishponds—I Two Species in Fishponds of the Chiba Prefectural Freshwater Fisheries Experimental Station

Abstract

At the Chiba Prefectural Freshwater Fisheries Experimental Station some species of freshwater ostracods have often multiplied tremendously in fishponds and became a source of nuisance to pond-cultured eels. Two species of the ostracods were brought in for identification. Specimens were fixed with alcohol, and dissected and embedded in Canada balsam. The species proved to be the following: one called “Naga-Kaimijinko” was identi-fied as Candonocypris assimilis and is named “Hainaga-Kaimijinko”; the other, “Maru-Kaimijinko”, was allotted to Heterocypris incongruens attenuata and named “Kawari Ibo-Kaimijinko”, both of which are new to Japanese fauna. The former has hitherto been found only in Oceania in spite of its vital powers; its right valve is complicated in the marginal structure. The latter has been confused with H. incongruens incongruens by some authors, but the scanning electron microscope photographs of valves may clarify the distinction between them. © 1975, The Japanese Society of Fisheries Science. All rights reserved.