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Show 1873.] DR. J. ANDERSON ON ASIATIC SHREWS. 229 membranous in character. There is only one of Hodgson's species in this museum,. S. soccatus (not C. nigrescens), represented by a single specimen identified by Blyth, while an individual referred by the latter naturalist to Elliot's P. niger is so shattered about the head that I have hesitated to remove the skull. None of Kelaart's species is represented, neither is any of the species described by Tomes and Templeton ; so that, if we exclude P. indica, P. murina, P. serpentaria, P. griffithii, S. soccatus, and P. nigra, the specimens in the museum are all Blyth's species. I have removed the skulls from as many of the museum specimens as possible; and the result of m y inquiries renders it probable that some of the so-called species are only young individuals, and others merely adolescents, of one and the same form, while others appear to be varieties depending on chromatic modifications of the fur. It would be premature, however, to venture any decided opinion on these instances until more materials are collected for comparison. The general characters of the form of the teeth of the four subgenera of Shrews, Sorex, Crossopus, Crocidura, and Pachyura, are the same; but tbe number of the teeth varies in the interspace between the front incisors of the upper jaw and the first molar, and in the intermaxillary bone. The known limits of the variation of the small lateral teeth in the foregoing interspace is 2 to 5, and in the intermaxillary bone from 1 to 3. The latter, of course, form one section of the inciso-molar interspace. The molars of the maxilla are 4 on each side, a number which prevails throughout the group. The mandible has always 12 teeth, viz. 1 front incisor, 1 lateral incisor, 1 canine, 1 premolar, and 3 molars on each side. The Shrews, for convenience, may be further separated into two great subordinate groups, dependent on the absence or presence of a brownish pigment deposit on the teeth. All the Shrews of the former division are characterized by the simplest type of dentition. The number of teeth in the maxilla varies from 7 to 9 on each side. In Shrews with the former number (Diplomesodon) the small lateral teeth in the inciso-molar space are two, with the intermaxillary suture between them, the dental formula being ^ + | + 2 ^ = 26*. The front incisor is arched ; and at its base there is a small obtuse tubercle. The intermediate type, with three small lateral teeth (Crocidura aranea), bas the maxillo-intermaxillary suture between the second and third small lateral teeth ; the front incisors have no process on their inner margins ; the dental formula is -2^ + 2 + 2+6= ^* The type with nine teeth on each side of the upper jaw has four small lateral teeth (Pachyura indica), the last very minute. Brandt has observed the suture between the second and third small teeth, an observation I have verified in a nest of three young speci- * I have obtained a short-tailed Shrew from Assam, having a large head, with this formula, but with hidden obscure external ears and very short tail, one sixth the length of the animal, and with scaly feet and legs, like a Mole, with the pelvis of that animal. It forms a new genus, which may be designated Pygmura. |
