抄録
A new species of dicyemid mesozoan, Dicyema koshidai sp. nov., is described from Shiroika, Sepioteuthis lessoniana Lesson, 1830, collected off Uozu in Toyama Bay and off Mihonoseki in the Sea of Japan. The dicyemid is a large species that reaches a length of about 5000μm. The vermiform stages are characterized as having 32-40 peripheral cells, a conical calotte, and an axial cell that extends to the middle of the metapolar cells. Infusoriform embryos consist of 37 cells; two nuclei are present in each urn cell and the refringent bodies are solid. The dicyemids live in folds of the renal appendages of the cephalopod host. This is the second dicyemid species to be described from S. lessoniana. Additional details of the first species, D. orientale Nouvel and Nakao, 1938, are described. The dicyemid fauna in S. lessoniana is discussed.
