MAMMALS COLLECTED BY DR. W. L. ABBOTT ON BORNEO AND SOME OF THE SMALL ADJACENT ISLANDS. By Marcus Ward Lyon, Jr., Assistant Curator, Division of Mammals, U. 8. National Museum. INTRODUCTION. Before collecting on the mainland of Borneo, Dr. W. L. Abbott made two expeditions to adjacent islands, the mammalian fauna of which is closely allied to that of Borneo. One of these expeditions was to the Natuna Islands, north of Borneo, and was made during the spring and summer of 1900; the other was to the Karimata Islands, off the west coast, during August and September, 1904. Lists of the mammals obtained on these expeditions were published by Mr. Gerrit S. Miller, jr., in 1901 and in 1906. x More recently Doctor Abbott has visited the mainland of Borneo five times, on each occasion stopping at some of the adjacent islands. An account of the mammals collected on the first trip to the mainland, covering the Kapuas River region, was published by me in 1907. 2 The present paper aims to give an account of the mammals obtained on the remaining four expeditions — two to southwestern Borneo and two to southeastern Borneo — as well as those collected in the near-by islands. For the sake of completeness, I have included in the present paper the species collected in the Kapuas River region, as well as those from Karimata Islands, the latter having been visited a second time. Four short papers 3 have appeared recently which i Proc. Wash. Acad. Sci., vol. 3, pp. 111-138, March 26, 1901. Proe. U. S. Nat. Mus., vol. 31, pp. 55-66, July 23, 190d. 2 Proc. U. S. Nat. Mus., vol. 33, pp. 547-572, December 24, 1907. 3 Lyon, Description of a new squirrel of the Sciurus prevostii group from Pulo Temaju, west coast of Borneo. Smiths. Misc. Coll., vol. 4S, pp. 275-270, February 4, 1907. Lyon, Remarks on the Insecfovores of the genus Gymnura. Proc. U. S. Nat. Mus., vol. 36, p. 449, May 27, 1909. Doctor Abbott's Bornean specimens listed. Elliot, On the genus Presbylis Esch., and Le Tarsier Bufion, with descriptions of two new species of Tarsius. Bull. Amer. Mus. Nat. Hist., No. 28, pp. 151-154, May 27, 1910. Describes the tarsier from the Kapuas River region. Elliot, Descriptions of some new species of monkeys of the genera Pithecus and Pygathrii collected by Dr. W. L. Abbott and presented to the United States National Museum. Proc. U. S. Nat. Mus., vol. 38, pp. 313-352, August 6, 1910. Describes the common macaques from Karimata, the Kapuas River region, Bawean Island, and Pulo Mala Siri. Proceedings U. S. National Museum, Vol. 40— No. 1809.