STUDIES ON THE SEASONAL CHANGES IN THE CHEMICAL CONSTITUENTS OF THE PEARL OYSTER

Abstract

Not only in morphology but also in metabolism many marked differences have been observed between Invertebrata and Vertebrata. Especially differences in the chemical process of calcification are typical. The mechanism of shell formation by the mollusks, however, has not yet been so thoroughly studied as the process of bone formation. Although a sort of pearls is produced by many kinds of bivalved mollusks, that of the pearl oyster, Pinctada martensii, is said to be superior. In the culture pearl industry or Japan, this kind of mollusk has been used almost exclusively (1)(2). It may be expected that the quality of the pearl formed by the pearl oyster is influenced by various external conditions under which the pearl oysters have been cultivated. For several years the process of calcification in the pearl oyster has been studied from the biochemical standpoint at this laboratory (3). The seasonal variations in the chemical constituents of the pearl oyster were first investigated. Especially, since the inorganic constituents are presumed to have close relation to the formation of the pearl and of the shell, their seasonal changes were precisely investigated.