Figs. 25, 27. Proechimys goeldii steerei, sex ?, "Hyutanaham," USNM no. 105537. × 1.
Figs. 26, 28. Proechimys goeldii goeldii, female, AMNH no. 37488. × 1.
Figs. 29, 30. Proechimys goeldii steerei, sex ?, USNM no. 105537, "Hyutanaham." × 1.
Figs. 31, 32. Proechimys goeldii goeldii, female, AMNH no. 37488, Fazenda Paraiso. × 1.
Skull.—Large and strong; rostrum rather pointed posteriorly; supraorbital ridges not much expanded and extending across anterior half of parietals; infraorbital foramen without groove for transmission of nerve, or groove obsolete; zygomatic arches slender; postorbital process of zygoma involving mostly squamosal; incisive foramen short and narrow (4.5 × 2.5 mm) with margins almost parallel or tapering gradually caudad and extending toward palate as ridges; posterior margin of incisive foramen approximately 2.5 mm anterior to premolars; vomerine sheath complete, with both elements well-developed; mesopterygoid fossa never extending anterior to middle of M3; bullae large, well inflated and with shallow grooves.
Teeth.—Upper molariform teeth: P4 with three counterfolds; upper molars with four counterfolds each or, less commonly, three. Lower premolars with four counterfolds; lower molars with three each.