Abstract
Bipalium hilgendorfi (VON GRAFF, 1899) (Turbellaria, Tricladida, Terricola) is a species described at first from the vicinity of Tokyo (an old name, Edo ; also spelled as Yedo or Yeddo), Japan, under the name of Perocephalus hilgendorfi ; the species was redescribed by KABURAKI (1922) based upon a single sexual specimen from Mt. Takao-yama, near Tokyo. This old species is redescribed in the present paper from a modern taxonomic viewpoint based upon sufficient material of the Sapporo locality. Living animals (55-80mm long and 4-5mm wide) have a depressed rotundate head and a light reddish brown coloration on the dorsal surface with a single, dark brown middorsal stripe and without stripes on the ventral surface. A large, muscular penis with a wide bulbar cavity, a well-developed glandular chamber with a tubular diaphragm, and the presence of a long common sperm duct and a short common ovovitelline duct are important taxonomic characters in the genital anatomy of this species. Some ecological conditions of the Sapporo locality are also described.
