206 Bulletin American Museum of Natural History. [Vol. XII, 



in coloration. A peculiar feature of the skull is the shortness of 

 the palatine foramina. 



Oryzomys trichurus, sp. nov. 



Type, No. 15328, $ ad., El Libano plantation, near Bonda (alt. 500 ft.), 

 Santa Marta District, June 29, 1899 ; Coll. H. H. Smith. 



Pelage ordinary. Color above strong yellowish brown, approaching ochra- 

 ceous, conspicuously lined with black ; sides, and especially the sides of the 

 face, ochraceous ; below uniform pure white to the base of the fur ; ears rather 

 small, brown, well covered externally with short yellowish brown hairs ; tail 

 considerably longer than head and body, heavily clothed with pale yellowish 

 brown bristly hairs, completely concealing the annulations ; fore feet whitish, 

 hind feet yellowish buff. 



Young in first pelage are yellowish gray-brown above, rather clearer fulvous 

 on the cheeks and sides, and pure white below to the roots of the hairs, as in 

 the adult. Tail hairy. 



Measurements. Type, total length, 281 mm. ; tail vertebrae, 160 ; hind foot, 

 23, with claws, 25 ; ear (in dry skin), 13. 



Skull, total length, 30; basal length, 22; zygomatic width, 15; mastoid 

 width, II ; interofbital width, 5 ; length of nasals, 10.5 ; palatal length, 5.3; 

 palatine foramina, 5 ; upper toothrow, 4 ; lower jaw, length (condyle to incisor 

 tips), 18 ; height (condyle to angle), 6.7 ; height at coronoid, 6.5. 



Oryzomys trichurus is based on an adult male and two young 

 (as skins, other young in alcohol), all from near Bonda. An 

 adult nursing female, also from Bonda, resembles the type in 

 measurements and coloration, and is indistinguishable also in 

 cranial characters, but has the tail nearly naked, possibly from 

 the wearing off of the hair. 



This species is at once recognizable by its heavily clothed tail, 

 pure white underparts, and strong fulvous coloration above. It 

 evidently belongs to the O. flavicans group, from which it differs 

 in its heavily clothed tail and pure white underparts. The tail 

 is as hairy as in Rhipodomys sumichrasti. O. flavicans illectus Bangs, 

 from Pueblo Viejo, Colombia, from an altitude of 8000 feet (O. 

 trichurus is from near sea level), is similar in most respects, but 

 has the underparts " a beautiful rich orange-buff to base of 

 hairs." A specimen in the Smith collection from Minca, altitude 

 2000 feet, is apparently intermediate between illectus and trichu- 

 rus, it having larger ears than trichurus, and being much deeper 

 colored above, with an orange ochraceous lateral band, the lower 

 parts strongly tinged with ochraceous, and the tail naked. This 



