[An error in the Reichert-Gaupp theory. A contribution to onto- and phylogenesis of the temporomandibular joint and ear ossicles in mammals].

The theory of Reichert- Gaupp is refuted by A) new embryological, B) some teratological and C) a new morphological and functional interpretation of palaeontological findings: A) Before the formation of the chondrocranium the still fibrous anlagen of the Meckel's cartilage and of the hyoidal (!) malleus-incus-complex are still sharply outlined each against other. The hyomandibular boundary between them is yet distinctly visible. B) In the malformations being reconducted to an arrest of development the malleus-incus-complex regularly shares the fate of the outer ear (II. visceral arch) but never the destiny of the face (I. visceral arch). The ossicle-chain is not only a functional but also an ontogenetic unit and consequently also a phylogenetic unit. C) The phylogenetic changes of the temporomandibulary joint (tmj) of the Therapsida result by steps out of autochthon (!) structures. The functional background is discussed. We see the articulare as homologue to the processus condylaris and the quadratum to the articular disk. The phylogenetic older quadrato -articular hinge-joint is preserved in the inferior part and the phylogenetic younger quadrato - squamosal slide-joint, which in the human embryo also develops 2 weeks later than the first, is situated superior to the ginglymus . Thus the Mammals have 2 tmj on each side but no squamoso -dental joint.