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Show 1881.] INDIAN SPECIES OF MUS. 539 in none of the numerous specimens of M. alexandrinus I have examined. This very handsome Rat m ay always be readily recognized by its brightly contrasted colours and its long bicolor tail. It is true that many specimens of Mus fulvescens have a somewhat similarly coloured body; but they always have the lower side of the tail of the same tint as the upper. I have placed "Mus octomammis" here rather than under M. fulvescens, for the reasons already mentioned under that species. The distribution of M. jerdoni presents some most interesting points. In Mr. A. R. Wallace's recent work, ' Island Life,5 the author, when treating of the islands of Formosa1 and of Java2, states that the fauna of each of these two widely-separated places has a noticeable connexion with that of the Himalayan region. N o w this species gives us a most interesting instance of the correctness of Mr. Wallace's views. Its headquarters seem to he in the Sikhim region ; but a very young specimen collected by Baron A. von Hiigel in Java is absolutely the same, it possesses even the minute fifth palate-ridge above mentioned ; its fur is somewhat shorter, and, considering its age, more thickly spinous than is the case in Himalayan specimens ; but these differences are only the natural result of a more tropical climate. With regard to Formosa, Mus coxinga, Swinh.3, of which the types are in the British Museum, is so very closely allied to this species that. I was at first disposed to consider it identical; but I now think it just separable on account of its longer hind foot (1*4 against 1*15). W e thus have, isolated in these three places, nearly related Rats which seem to be quite un« known in the intermediate districts. Mus (Nesokia) nemorivagus presents us with another instance of this sort of distribution, being found in Nepal and Formosa; and if, as is just possible, the true M. setifer, Horsf., from Java, is the same, we have a still better example of the relations of these faunas to one another. Mus jerdoni seems to be almost entirely a highland species. Those I have seen have come from Darjiling (7000 ft.), Khasya Hills (4000-5000 ft.), and Willis Mt., Java (3000 ft.). Jerdon4 mentions specimens from Kunawar (12,000 ft.); but, from the locality, I a m inclined to think that they may have been M. niveiven-ter. Dr. Anderson tells m e that these Kunawar specimens are not now in the Calcutta Museum; so that the question of the western distribution of this species cannot be settled at present. W h e n Blyth originally described M. jerdoni he stated that the head and body measured 4 inches and the tail 3 | inches, proportions wholly at variance with those given above ; but I am informed by Dr. Anderson that the type is only half-grown, and that specimens in the Calcutta Museum, undoubtedly identical, measure just about what those do of which the dimensions are given. Mr. Blyth described this Rat as a species of the subgenus Leggada, on account 1 Chap, xviii. p. 375. . . l^P* xvii* P* 358- s p Zi S 1864 p. 185 (misprinted coninga, see P. Z. S. 1870, p. 636). * M a m m . Ind. p. 209 (1867). |