Goldman — New Mammals from Central and South America. 239 



ankles by a dusky band below which the white is continued along inner 

 side of metatarsus to toes; fore feet and outer side of metatarsus pale 

 brownish; nose and ears blackish, the latter nearly naked as usual in the 

 group; tail brownish above, grayish below. 



Skull. — Similar in general form to that of trinitatis, hut rostrum 

 broader above, less compressed over roots of incisors; supraorbital ridges 

 heavier; audital bullae decidedly larger, more inflated; temporal ridges 

 absent as in trinitatis; dentition about the same, except that there are 

 four transverse furrows or enamel islands in the lower premolars of rive 

 skulls examined, instead of three as in the three skulls of trinitatis availa- 

 ble for comparison. 



Measurements. — Type (dry skin): Total length, 347; tail vertebrae, 

 122; hind foot, 49. Skull: Greatest length, 53.8; eondylobasal length, 

 48; zygomatic breadth, 26; length of nasals, 19.3; interorbital breadth, 

 11.9; length of palatal bridge, 10.5; alveolar length of upper molariform 

 toothrow, S.5. 



Remarks. — This spiny rat is a member of the same group as trinitatis 

 and mincae, hut differs in important respects from both and 1 am unable 

 to associate it very closely with any of the other species described. In 

 dentition it agrees with trinitatis, the type species of the genus, in the 

 possession of three transverse furrows, or elongated enamel islands in 

 most of the molariform teeth. This character is somewhat variable, how- 

 ever, in trinitatis and other species, the number in the lower molars being 

 sometimes reduced to two. The furrows may also become divided through 

 wear and the normal number thus obscured through the multiplication 

 of enamel islands. 



Specimens examined. — Five, all from the type locality. 



