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Show 1897.] BLUE BEAR OF TIBET. 419 ologists, in Ursus spelceus (fig. 1) this tooth is short and has two very large tubercles. Buskl considered that only one of these tubercles (the posterior) is represented in the corresponding tooth of the typical U. arctus group, and apparently regarded the anterior tubercle as distinct. I cannot, however, but consider them as homologous, and I think Busk has attached far too much importance to them, as also to the structure of the talon in the same tooth. Fig. 1. a h 1 Fourth right lower premolars of Ursus spelceus (1) and U. arctus isabellinus a, anterior ; b, posterior tubercle. 1. URSUS ARCTUS FOSSILIS.-Pleistocene Brown Bear. Ursus fossilis, Goldfuss, Nova Acta Ac. Caes. Leop.-Car. vol. x. pt. 2, p. 259 (1821); Busk, Trans. Zool. Soc. vol. x. p. 64 (1877). Ursus prisms, Cuvier, Ossemens Fossiles, vol. iv. p. 380 (1823). Ursus ferox fossilis, Busk, Phil. Trans. 1873, p. 546. According to Busk, the Brown Bear of the English caverns and Irish peat-bogs is much nearer to the Grizzly than to the European Brown Bear, which first makes its appearance in the English fen-deposits. In this determination he relies chiefly on the characters of the skull and the large size and structure of the fourth lower premolar. Although, as I shall show presently, one of the characters of the latter tooth on which he lays stress is not constant, yet I feel bound to accept the general conclusions of one who has devoted so much labour to a very difficult subject. It is important to notice that he regards the Brown Bear from the Gibraltar caverns as probably intermediate between U. arctus fossilis and U. arctus Isabellinus. As already said, if his conclusions are correct we must regard U. arctus fossilis as the ancestral stock from which have sprung all the other members of the group. 2. URSUS ARCTUS TYPICUS.-European Brown Bear. Ursus pyrenalcus, F. Cuv. Hist. Nat. M a m m . livr. xlv. (1824). Ursus norveygicus, F. Cuv. op. cit. livr. vii. Ursus cadavarlnus, Eversmann, Bull. Soc. Moscou, 1840, p. 8. Ursus formlcarlus, Eversmann, loc. cit. Myrmarctos eversmannl, Gray, Proc. Zool. Soc. 1864, p. 695 ; Cat. Carniv. Brit. Mus. p. 232 (1869). Under this name may be included tbe living Bears of Europe at 1 Trans. Zool. Soc. vol. x. pp. 65, 66 (1877) a |