抄録
1) The investigations on the mechanism of layer formation in several marine bivalves were carried out with radioautographic stripping films.
2) The distribution and concentration of labeled calcium may indicate the mode of layer formation.
3) The circular deposition of labeled calcium on the inner shell surface appeared to be essentially similar to the selective fixation of calcium in the organic matrix and among various layers.
4) The mechanism of formation of the spiral steps and growth hills must be theorized on possible ideas independent of the position of development of embryos of mineral crystals which seems to be determined in certain specific fragments of the conchiolin protein.
5) The mechanism of development of growth hills in the nacre and the calcitostracum seemes to be respectively understood on essentially different ideas. That is, the mechanism of formation of spiral growth steps in the nacre can be consistently explained by the theory of screw dislocation, while the growth hills in the calcitostracum by the theory of dendritic growth.
