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Show 60 MR. O. THOMAS ON THE MAMMALS OF [Jan. 19, I cannot agree with Dr. Anderson as to the identity of the genera Pteromys and Sciuropterus, which he has united on the plea that the dentition is much the same in both, and that the distichous arrangement is not purely distinctive of the smaller species, but is found partially in some of the larger, while, on the other hand, some of the so-called Sciuropteri really have bushy tails. He goes on to say, " The wing-parachute in all the members of the group is the same, although some naturalists have described it in sagitta as having an expansion in front of the fore limb which does not exist in the other species ; but this is unquestionably an error." In order to settle the question, I have examined specimens in spirit both of Pteromys and Sciuropterus, and I find that not only do both have an antebrachial membrane, arising from the back of the cheek and inserted in the front of the carpus, but that there really are important differences in the development and insertion of the parachutes, comparable in some respects to those observable in the wing-membranes of the Chiroptera, differences which, as in the case of the antebrachial membrane, Dr. Anderson must have overlooked through examining dried skins only. In Pteromys there is a broad well-defined interfemoral membrane, inserted externally at the point where the tendo achillis is attached to the calcaneum, and internally to the tail from two to three inches from its base, and there is in some of the larger species nearly three inches depth of membrane clear of the hind limb. On the other hand, in Sciuropterus there is either no interfemoral membrane at all, or what there is merely consists of a slight expansion of skin behind the knee, attached externally to the tendo achillis, about halfway down, and internally to the hinder side of the hips and never involving any part of the tail. The lateral membrane also is distinctly narrower, especially below the knee, in Sciuropterus than in Pteromys, although the longer fringes of hair in the former hide this fact in dried specimens. Adding to these differences the well-known one in the arrangement of the hairs of the tail, to which I am unable to see the exceptions mentioned by Dr. Anderson, and also those in the dentition described by various authors, I think that it will be admitted that two such natural groups as Pteromys and Sciuropterus should be allowed to stand as distinct genera. 8. SCIUROPTERUS PEARSONI. Gray. a. Machi, 7/5/81. This rare species would be naturally expected to occur in Manipur. It has previously been recorded from Sikkim, Assam, and Yunnan. 9. SCIURUS INDICUS, Erxl. a. cS . Gurung R. 8/2/81. The present is by far the most easterly locality as yet recorded for this species, and extends its known range very considerably, the Terai region of Nepal (Hodgson) and Cuttack (Anderson) having |