ON THE DEVELOPMENT OF DENTIN IN FISH

II. TELEOSTEI

¹ University of California College of Dentistry, San Francisco, Calif.

The collagenous fibers of the dentin in osseous fish can be classified into two groupings by their direction and coarseness. First, argyrophil fibers from the dental papilla are so arranged as to form a layer of coarse, longitudinally arranged fibers. In certain species (Merluccius merlucius), the whole outer dentinal layer is of this type.

In Gobius niger, Labrus bergylta, and Ctenolabrus rupestris, a second zone of dentin with radially arranged, finer fibers is found between the longitudinally arranged, coarse fibers and the columnar epithelium of the tooth germ. This forms the outermost layer of the tooth from the mesodermal enamel to the basal edge of the tooth.

The formation of collagenous fibers proceeds so rapidly that a sharp boundary is created between the peripheral papilla cells and the newly formed dentin.