THE STRUCTURE OF OS-MALLEUS IN PALAEOARCT IC MUSTELIDAE (CARNIVORA)

The size and structure of mallei in 20 species of Mustelldae from the Palaearctic were studied. The results enabled us to discriminate 8 gro ups of genera: 1) Enhydra, 2) Lutra, 3) Mellivora, 4) Meles, 5) Gulo, 6) Charronia, Martes 7) Vormela, 8) Mustela, These groups correspond t o the subfamilies of Mustelidae proposed by Pocock (1921). The conside rable differences between M. putorium and M. eversmanni and isolated p osition of M. erminea are noted. The mallei of M. lutreola and M. sibi rica are very similar. The main paths of the evolution of the malleus in Mustelidae are as follows: collium broadens and shortens, therefore , the angle between the base of manubrium and collium decreases; lamin a becomes narrow (from Charronia to Martes, from Gulo to Meles) and de creases; the medial excision of lamina closes (from Lutra to Enhydra), its size decreases; the position of manibrium straightens (Mustela+ Vormela); the caput of malleus increases. The increase of caput in Mus tela and Vormela, as compared to Lutra and Enhydra and especially to G ulo, Meles and Martinae, is correlated with the increase of the articu lar surface and, probably, with the increase of incus.