Until now it is well known that throughout life the endochondral layer of human labyrinthine bone consists of a "woven, alamellar, fine-fibred type of bone" which is called "embryonic skein bone" (embryonaler Strähnenknochen) (MEYER 1927). In the present study different types of osteons in endochondral layer are described. According to KNESE and TITSCHAK'S (1962) classification of osteons these structures appear almost identical to developing osteons. They exist of woven bone or of woven bone containing lamellar fragments. There are osteons which consist of bundles of skein bone and which are not visible in long bones. Especially considering the embryologic character of endochondral layer the classification of "vascular mantles"(MANASSE 1914) is discussed.