Abstract
1) Growth hills on the inner surface of the calcitostracum in Chlamys nobilis were observed with optical and electron microscopes and discussed in comparison with those in Anomia lischkei and Ostrea gigas.
2) Growth hills occurred in the central area of the shell valve as in A. lischkei and O. gigas.
3) The relation between crystal structure and habit was determined from elctron diffraction patterns.
4) Characteristic spiral growth hill as in the other calcitic shells reported previously was never found in the Chlamys shell.
5. The mechanism of development of the growth hill in calcitic shells was discussed.
6) It is possible to the epitaxial growth of mineral crystal and organic matrix.
