no. 1809. MAMMALS FROM BORNEO AND VICINITY— LYON. 81 



SCIURUS BORNEOENSIS BORNEOENSIS (Miiller and Schlegel). 



1907. Sciurus borneoensis borneoensis, Lyon, Proc. U. S. Nat. Mus., vol. 33, p. 552, 

 December 24, 1907. 



Ten specimens from the Kapuas River region, northern bank, and 

 inland on the higher ground, collected in 1905. 

 See figure next to the top one on plate 4. 



SCIURUS BORNEOENSIS PALUSTRIS Lyon. 



1907. Sciurus borneoensis palustris Lyon, Proc. U. S. Nat. Mus., vol. 33, p. 553, 

 December 24, 1907. 



Fifteen specimens from the Kapuas River region, northern bank, 

 and in the lowlands, collected in 1905. 

 See top figure on plate 4. 



SCIURUS CARIMATA Miller. 



1906. Sciurus carimatx Miller, Proc. U. S. Nat. Mus., vol. 31, p. 57, July 23, 1906. 



In addition to the original series of specimens collected on Kari- 

 mata Island, Doctor Abbott secured three additional specimens in 

 1908. 



(For measurements, see table, p 83.) 



SCIURUS PROSERPINA Lyon. 



1907. Sciurus proserpinse Lyon, Smiths. Misc. Coll., vol. 48, No. 1659, p. 275, 

 February 4, 1907. 



Since securing the two original specimens of this species in 1905, 

 Doctor Abbott took three others from Pulo Temaju in 1907. They 

 differ in no respects from the earlier specimens. 

 (For measurements of the series, see table, p. 83.) 

 The relations of this squirrel are with Sciurus borneoensis palustris 

 and S. borneoenis borneoenis from the adjacent mainland of Borneo 

 on the north side of the Kapuas River. This is most clearly shown 

 by its gray tail. The squirrels of the S. prevostii group from the 

 islands of Karimata, Pelapis, and Panebangan, with their solid black 

 tails and brightly colored underparts, are clearly related to Sciurus 

 sanggaus from the mainland of Borneo south of the Kapuas River. 

 The relationships of these squirrels and the positions of the islands 

 on which they occur would indicate that the Kapuas is an ancient 

 river, and has long separated the gray-tailed group of squirrels from 

 the black-tailed group, and that as the land has subsided members 

 of the two groups have been left on the elevated portions of the land, 

 now forming islands to the north and south of the Kapuas. The river 

 is thus older than the islands. Should prevostii squirrels be found on 

 Pulo Lamakotan or Pulo Kabung they would probably be found to 

 belong to the gray-tailed group. 

 80796°— Proc.N.M.vol.40— 11 6 



