抄録
A northern fur seal, Callorhinus ursinus, captured off the coast of Hanasaki, Hokkaido died in the Marine Aquarium in January, 1980. A total of 283 mature and immature mites were collected from the nasal cavity. Mature mites are elongated in the posterior part of body to form a club-shape with the rounded posterior extremity. Ten to 12 transverse rows of 8 to 12 sharp denticules each and a few rows of minute spines are present on the ventral surface of the capitulum and the posterior surface of coxa III, respectively. From these morphological characteristics the present specimens were identified as Orthohalarachne attenuata (Banks, 1910). Pathological changes in the affected sites by the mites were the marked abrasion of the mucosa and the destruction and necrosis of the deeply placed tissues by the action of the legs, palps and chelicerae of the mites.
