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Show 1892.] MR. O. THOMAS ON MAMMALS FROM NYASSALAND. 549 Firstly, they prove conclusively that the latter species has a seasonal change of colour, the two coats being the one a grizzled rufous and the other a grizzled grey. Peters's type, as figured by him, was a changing specimen with the anterior half of the body grey and the posterior rufous. Specimen a is in very much the same state, and in my opinion unquestionably belongs to the same species. From the relative lengths of the two sorts of fur, it is evidently changing from the rufous to the grey phase, and the latter is therefore obviously the summer form. In specimen b, killed a month later, the change has gone a little further, the grey fur having become as long as the rufous, while the latter has much decreased in area; the hairs on the centre of the back are deep black to their roots. Of the three co-types of S. shirensis, Gray, one, young, is in the rufous state, except that its extremities ere grey, but the two adults are both wholly in their grey coats. They are, however, quite uniform in colour, and have no black patches on their backs. All the specimens examined have one premolar only in the upper jaw, although Peters's type was said to have two, and on this account S. mutabilis and S. shirensis were kept apart in Dr. Jentink's monographs of the African Squirrels l. M y own conclusion is that the new Nyassa specimens, with one premolar, are certainly S. mutabilis, a determination which destroys the importance of the presence or absence of the extra premolar in this form, and then, this character being gone, that there is nothing to separate the two forms but the black dorsal patches of mutabilis, and that as to these we must be content to wait until further specimens prove them to be due either to individual variation, to advanced age, or to genuine specific distinction. But the fact that the types of S. shirensis came, as their name implies, actually from the River Shire is strongly in favour of their specific identity with Mr. Johnston's Nyassa examples. 7. SCIURUS PALLIATUS, Peters. a,b. 3 2- Milanji Plateau, 6000 ft. 29/10/91. c. 3. Milanji Plateau, 6000 ft. 2/11/91. 8. OTOMYS IRRORATUS, Brants. a. Ad. al. 2 • Like specimens of this species collected by Mr. Jackson in Mianzini2, Masailand, this individual has a molar lamina-formula n 3-2-7 0 1 4-2-2' 9. GERBILLUS (TATERA) AFER, Gray (?). a-d. 4 in al. The South African species of the subgenus Tatera are so little 1 N. L. M. iv. p. 18 (1882). Dr. Jentink, however, implies that some doubt exists as to the skull in Peters's type-skin really belonging to it. 2 See P. Z. S. 1801, p. 184. |
