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Show 720 ON THE MALAGASY GENUS BRACHYUROMYS. [June 1, Brachyuromys &c, i. e. the preservation of primitive types of Murldce \ Theirs is a parallel to that of the African insectivorous family Chrysochlorldce, as compared with the more generalized memebrs of the Malagasy family Centeildce. Whilst the somewhat closer agreement with Brachyuromys than with the rest of Malagasy Eodents may in the case of Rhizomys, Spalax, and Siphneus be due to the circumstance that in each the molars are hypselodont (though in a much lesser degree in Brachyuromys), the case seems to be different with regard to Tachyoryctes. This latter is in the pattern of its molars almost identical with one of the species of Brachyuromys (B. ramlrohltra). The mutual relations of the Hesperomyince, Microtince, Murince, and Spalacidae with each other and with the Malagasy Nesomylnce have thus to a certain extent been cleared up by a better acquaintance with the latter. EXPLANATION OF THE PLATES. PLATE XXXVII. Fig. 1. Skull of Brachyuromys betsileoensis (Bartl.): fig. 1, side view; la, from below ; 1 b, from above ; 1 c, front view. 2. Skull of B. ramirohitra, Maj.: fig. 2, side view; 2a, from below; 2 b, from above; 2 c, front view ; 2 d, side view of mandible. 3. Skull of Tachyoryctes splendens, Riipp.: fig. 3, side view; 3 a, from below ; 3 b, from above; 3 c, front view. All figures nat. size. P L A T E XXXVIII. Different views of the skull of Bhizomys sinensis, Gray. Nat. size. Fig. 1, side view ; fig. 2, from above; fig. 3, from below ; fig. 4, from behind ; fig. 5, oblique view of left infraorbital foramen; fig. 6, postero-superior part of left mandible, from behind. PLATE XXXIX. Figs. I a-8 a. Upper molars of Brachyuromys and Tachyoryctes, enlarged. 1 6-8 b. Lower molars of ditto. 1 a-3 b. Brachyuromys ramirohitra, Maj. 4 a-4 b. Tachyoryctes annectens, Thos. 5 a-6 b. T. splendens, Riipp. 7 «-8 b. Brachyuromys betsileoensis (Bartl.). PLATE XL. Figs. 1 a-7a. Upper molars of various species of Rhizomys, enlarged. 1 6-9 b. Lower molars of ditto. 1 a-3 b. Rhizomys badius, Hodgs. 4 a, 4 b. R. pruinosus, Blyth. 5 a-6 b. R. sumatrensis (Raffles). 7 a-8 b. R. sinensis, Gray. 9b. R. sivalensis, Lyd. 1 Still more striking instances amongst Rodentia of adaptation as a preserver of primitive types are afforded by the Aplodontidce and the Leporidce; both of them very primitive Rodent families showing the curious combination of some ^ery specialized features with their primitive characters. |
