On a New Species of Lepeophtheirus (Copepoda parasitica) from Pseudopleuronectis americanus Walbaum

IN EARLY APRIL 19'61 while I was looking for parasitic copepods in fish specimens preserved in our specimen gallery, I discovered ·twO different kinds of parasite coexisting on a single flat-fish, Pseudopleuronectis americanus Walbaum (26.5 cm long). Some of them, 19 in number, were found on the inner margin of the operculum, and have been identified as the present new species. The other 22 individuals, restricted to the gill filaments, were identified as belonging to the Lernaeopodidae. Because I do not have complete references at hand, I shall leave them to be studied later. It is interesting to find two kinds of parasites belonging to two different families on the same fish. It is regrettable that the locality and collecting date of the host of these parasites are unknown, but it is believed that this fish was not collected from near the Island of Formosa, since, up to the present, Pseudopleuronectis ame-ricanus is reported only from American waters. Moreover, this flat-fish was not collected recently, but has been preserved for at least 17 years. Fortunately, however, the parasites in its branchial chambers have remained unchanged. I am indebted to Dr. Yu-hsi Mohze Wang, chairman of the Department of Zoology, National Taiwan University, for reading the preliminary draft of my maquscript, and to Mr. Tchaw-Ren Chen for identifying the host fish for me,