_Skull._--Slender; bullae small but well-inflated; upper edge of jugals deeply concave; transverse ridge of jugals conspicuous; postorbital process of zygoma small, involving only squamosal; incisive foramen elongate (5 x 2.5 mm); vomerine sheath almost always incomplete, and maxillary part lacking or, when present, slender; mesopterygoid fossa extending forward as far as middle of second molars; posterior palatine foramina at plane of front border of first molars or slightly anterior thereto. _Teeth._--Upper molariform teeth with two counterfolds in 10 of 16 specimens and only one in remainder; these folds commonly coalesced; M3 with only one counterfold in 6 specimens, and 2 counterfolds in remainder. Lower molariform teeth with two counterfolds in 6 specimens and in 10 of them m3 has only one counterfold. _Comparisons._--From _P. i. panema_, _gratiosus_ differs in: Lower molariform teeth with only one counterfold in smaller percentage of specimens; incisive foramen shorter; aristiforms narrower; setiforms Ochraceous-Buff instead of Cinnamon. Differences from _iheringi_ and _paratus_ are given in the accounts of those subspecies. _Remarks._--All the animals were captured in climax forest. _Specimens examined._--Total number, 16 (MN), from Brazil, Espirito Santo, _Santa Teresa_, Floresta da Caixa Dagua, altitude 750 meters. =Proechimys iheringi panema= subspecies nova _Type locality._--Campinho, _Colatina_, Espirito Santo, Brazil; altitude 500 meters. _Type_: Museu Nacional, no. 8288, adult female; collected on 15 July, 1942, by C. Lako. _Range._--Known only from the type locality. _Diagnosis._--Aristiforms moderately wide; tail of approximately same length as head and body; setiforms Cinnamon; incisive foramen moderately long and narrow; vomerine sheath incomplete; upper molariform teeth with two counterfolds, but m3 most frequently with one. _Pelage._--_Aristiforms on middorsal region_: Gray basally, gradually blackening toward tip; total length, 21 to 23 mm; maximum width, 0.8 mm. _Aristiforms on outer thighs_: Gray, some gradually blackening toward tip and others with distal part Cinnamon; total length, 17 to 19 mm; maximum width, 0.7 mm. _Setiforms on middorsal region_: Gray, gradually blackening toward tip, but interrupted by Cinnamon, subapical zone; total length, 18 to 20 mm; maximum width, 0.06 mm. _Setiforms on outer thighs_: Gray, gradually blackening toward middle, and Cinnamon on all of distal parts or with tip blackish; total length, 13 to 15 mm; maximum width, 0.09 mm.