THE STUDY OF THE MINERAL COMPONENT IN CHITINO-PHOSPHATE SHELLS OF RECENT BRACHIOPODS AS CONCERNED WITH THE PECULIARITIES OF THE DEEP-SEA ORGANISMS

Smooth X-ray diffraction patterns was carried out for apatite in the s hells of recent species of the Lingulidae family (for shallow-water sp ecies Lingula anatina and L. reevi) and Discinidae family (for shallow waters species Discinisca lamallosa and deep water species Pelagodisc us atlanticus). The discinid shells differ from the lingulid ones not only in high content of organic component (chitin-like) matter, but al so in weak crystalized apatite. It is supposed that both features are useful for penetrating of discinids into the deep sea. Parameters of c rystalline elements are calculated. Francolitisation of apatite in sub fossil shells is shown.