382 EXTINCT AND VANISHING MAMMALS 



extinct as a result of the introduction of non-native old world 

 rats. Examples of Rattus rattus alexandrinus were taken dur- 

 ing the same visit to James Island on which the specimens of 

 N. swarthi were secured." Heller (1904) remarks that "leav- 

 ing out of consideration Albemarle, James, Charles, and 

 Duncan, the islands which are inhabited by introduced species, 

 it seems remarkable that large islands like Abingdon, Bindloe, 

 and Hood should lack indigenous species of Muridae [Criceti- 

 dae]. A careful search, however, failed to discover any mam- 

 mals on these islands. It is probable that James, Duncan, and 

 Albemarle islands, intervening between the ranges of the two 

 species of Nesoryzomys, were until recently inhabited by 

 indigenous species of this genus which became extinct upon 

 the introduction of" the house rats. This suggested distribu- 

 tion is now partly substantiated through the subsequent dis- 

 covery of Nesoryzomys of a related type on James Island. 

 Moreover, the fact that Heller failed to find it in 1898-99, 

 while Hunter secured four specimens in 1906, merely shows 

 how elusive small mammals may be, even when sought for by 

 so skilled a collector as Heller. 



DARWIN'S RICE RAT 

 NESORYZOMYS DARWINI Osgood 



Nesoryzomys danvini Osgood, Field Mus. Nat. Hist., zool. ser., vol. 17, p. 23, July 12, 



1929 (Academy Bay, Indefatigable Island, Galapagos group). 

 FIGS.: Orr, 1938, pi. 25, figs. 4, 4a (skull). 



From its nearest island relatives, N. indefessus and nar- 

 boroughi, this species differs in its decidedly smaller size and in 

 its bright fulvous coloration, which extends to the entire under 

 parts. The skull is slender and without sharp ridges or angles. 

 Total length, 222 mm.; tail, 89; hind foot, 27; length of skull, 

 30. 



This small, bright-colored species is remarkable in that it 

 furnishes the only instance known of two species of the genus 

 occurring side by side on the same island, "indicating a dis- 

 tinction of long standing." Three specimens were taken at 

 Academy Bay and a fourth at Conway Bay, Indefatigable 

 Island, while on the same dates 12 examples of N. indefessus 

 were taken at the former and 13 at the latter locality, indicating 

 that it is probably much the less numerous. Orr (1938) records 



