140 Fretp Museum or NATuRAL History — Zo6iocy, Vor. X. 
whole Bogota region and, as in the case of C. goudotiz, it may mean that 
the specimen actually had its source in the savannas east of Bogota 
near the Meta River. Pucheran’s figure, however, shows a pair of 
horns of somewhat unusual character, not referable with certainty to 
any known species. The disposition of the name columbicus, therefore, 
awaits competent examination of the type in the Paris Museum. 
Rhipidomys fulviventer elatturus subsp. nov. 
Type from Paramo de Tama, head of Tachira River, Venezuela. 
Alt. 7,000 ft. No. 18691 Field Museum of Natural History. Adult 
male. Collected March 3, 1911, by W. H. Osgood and S. G. Jewett. 
Original No. 4252. 
Characters—A small Rhipidomys, smaller than any previously 
described species of the restricted genus; general characters and colora- 
tion essentially as in R. fulviventer, but belly paler, tail shorter, hind 
foot smaller, and audital bullz smaller. Upper parts practically 
uniform tawny ochraceous evenly and finely mixed with dusky; a 
slight tawny ochraceous line; ears and tail sooty brown; under 
parts creamy white, lightly washed on the middle of the belly 
‘with pale tawny, the hairs, except those of the chin, with dark slaty 
bases. 
Measurements—Type and adult female topotype, respectively: 
Total length 225, 225; head and body 108, 108; tail 117, 117; hind foot, 
with claw 24, 23. Skull of type: Greatest length 28.2; basilar length 
21.4; zygomatic breadth 15.6; interorbital constriction 4.3; nasals 11.3x 
2.9; interparietal 10.7x3.9; palatine foramina 5.7x2; diastema 7.4; 
upper toothrow 4.5. 
Remarks.—This form is well distinguished from fulviventer but in 
the present unrevised condition of the genus, its relationship is con- 
veniently indicated by the trinomial. Typical examples of fulviventer 
have not been available for use in the present connection and con- 
clusions have been based upon the original description supplemented 
by specimens from eastern Peru referred to fulviventer by Oldfield 
Thomas. 
It is not improbable that the rats of this genus are more restricted 
within the boundaries of continuously forested areas than those less 
arboreal in habit. Relatively small discontinuities of forest, therefore, 
may be locally more effective factors of isolation than temperature 
and altitude. 
