Fig. 1

A well-preserved specimen of Polyptychoceras pseudogaultinum (Yokoyama, 1890), UMUT-MM19881a from Hokkaido Island, Japan, coated with ammonium chloride. In this individual, the paper clip-like shell is composed of four straight shafts running almost in parallel connected with U-shaped tubes. Scale bar represents 10 mm. The repository of this specimen is the University Museum, University of Tokyo. For detailed locality, see Okamoto and Shibata (1997)