_Proechimys elegans_ Tate, 1935, Bull. Amer. Mus. Nat. Hist., 68(5):400; Ellerman, 1940, The families and genera of living rodents, Brit. Mus. (Nat. Hist.), 1:119. _Type locality._--Lagoa Santa, _Nova Lima_, Minas Gerais, Brazil. _Type_: Syntypes in Universitets Zoologiske Museum, Kjöbenhavn; collected by P. W. Lund. _Range._--Known only from the type locality. _Diagnosis._--Aristiforms wide; P4 usually with two counterfolds; M3 sometimes with two counterfolds; p4 with two counterfolds anterior to main fold. _Pelage._--_Aristiforms on middorsal region_: Gray basally, gradually blackening toward tip; total length, 18 to 20 mm; maximum width, 0.7 mm. _Aristiforms on outer thighs_: Gray basally, gradually blackening toward tip which is Cinnamon; total length, 15 to 17 mm; maximum width, 0.3 mm. _Setiforms on middorsal region_: Whitish basally, gradually blackening toward tip, but interrupted by Cinnamon, subapical zone; total length, 17 to 19 mm; maximum width, 0.04 mm. _Setiforms on outer thighs_: Whitish basally, gradually blackening toward tip but interrupted by near (15''_a_) Cinnamon, subapical zone; total length, 10 to 12 mm; maximum width, 0.03 mm. _Skull._--Short; rostrum short but not stout; length of nasals 17 mm; bullae large, smooth, and well-inflated; jugals with conspicuous, transverse ridge; postorbital process of zygoma long, spiniform and constructed entirely of jugal; incisive foramen narrow (4 × 1.7 mm); vomerine sheath complete and slender; posterior palatine foramina obsolete; mesopterygoid fossa extending anteriorly as far as middle parts of second molars. _Teeth._--Incisors orthodont. P4 usually with two counterfolds, rarely with three; upper molars with only one counterfold, but M3 sometimes with two, posterior one being vestigial. Lower molariform teeth: p4 with two counterfolds, both being anterior to main fold; molars with only one counterfold. _Comparisons._--Differences from _P. s. setosus_ are given in the account of that subspecies. _Remarks._--According to Lund, these animals are found in the vicinity of small pools, swim well in spite of not having webbed toes, at night go after food and climb the corn stalks, and have their nests in the grass at the margins of the pools. _Specimens examined._--Total number, 2 (UZM), from Brazil, Minas Gerais, _Nova Lima_, Lagoa Santa. =Proechimys albispinus= (Is. Geoffroy)