Silurian Chitinozoa from Gotland

Silurian chitinozoans from 475 localities in the Late Llandoverian through Ludlovian of Gotland, Sweden, are discussed. Sixty-four species are described. One genus, Gotlandochitina, and thirty-two species are described as new. The micromorphology of the ornamentation, appendices, prosome, operculum, and vesicle wall is discussed. The abundance and diversity of the chitinozoans of Gotland have been calculated and are discussed in connection with a palaeoecologic interpretation. A method for calculating the productivity in oceans of earlier times is briefly sketched. The systematic position of the chitinozoans is discussed, and it is concluded that they were eggs of polychaetes and gastropods. The local range zones of the chitinozoans in the Silurian of Gotland are established, and some consequences in the correlation are indicated.