Costasiella usagi Ichikawa, 1993
Comment is not registered
The large eyes lie close together between the bases of the simple rhinophores. The anterior corners of the foot are tentaculiform and the tail is long and pointed. The head and the tail are not pimented, and the rhinophores are black. The median cerata are grey, while the outer ones are black. All the cerata possess a white end with a black tip. Moreover, all the cerata bear longitudinal striations reaching from the base of each ceras to the white apical portion. The cerata are arranged in about 10 rows. The ventral side of the foot is white.