抄録
Giant spider crab, Macrocheira haempferi (TEMMINCK), with a median rostral tooth instead of a pair of rostral spines, and Japanese spiny lobster, Panulirus japonicus (VON SIEBOLD), with the heteromorphic antennule in place of right eyestalk, are recorded respectively from Suruga Bay and the coast of the Boso Peninsula, central Japan. It is definitely said that the malformation of the rostrum is caused by the extended true rostrum being not descended during its development as a septum of the antennular fossae of both sides. On the other hand, the heteromorphic antennule is rather rare in the field, only with some records in spiny lobsters and crawfishes, and also in a freshwater atyd shrimp, but HERBST (1895-1916) and some recent authors experimentally caused the heteromorphic antennules not only in the shrimps and lobsters, but also in the hermit crabs and porcelain crab. According to them, the heteromorphic antennules are functional in response to mechanical and olfactory stimulation, and such heteromorphosis is produced only when the optic ganglion is severed along with eyestalk.
