Comparisons.—From P. g. goeldii, steerei differs in: Back and sides with more reddish; narrower interorbitally and across zygomata; palatilar length less and nasals shorter; maxillary part of vomerine sheath thicker; usually four instead of three counterfolds in M3.
Remarks.—This subspecies is clearly related to P. goeldii. One skull from Porto Velho, Rio Madeira, Guaporé, Brazil (CNHM no. 21558) may belong to an unnamed subspecies but is provisionally included here.
In the field notes of Professor Joseph Beal Steere, an entry for no. 72 reads: "Big white bellied wood rats x two young found in nest of grass on the ground with the two young—much darker young female." No. 77 in his field notes corresponds to the type specimen.
Specimens examined.—Total number, 4, from Brazil, as follows: Amazonas. Lábrea, Hyutanaham, 3 (USNM); Territ. Guaporé, Porto Velho, 1 (CNHM).
Proechimys goeldii goeldii [Thomas]
Proechimys goeldii [Thomas], June 1905, Ann. Mag. Nat. Hist., 15 (ser. 7):587, (orig. descr.); [Thomas], 1912, Ann. Mag. Nat. Hist., 9 (ser. 8):89; [Thomas], 1920, Ann. Mag. Nat. Hist., 6 (ser. 9):277, [Tate], 1935, Bull. Amer. Mus. Nat. Hist., 68(5):400; [Osgood], 1944, Zool. Ser. Field Mus. Nat. Hist., 29(13):199.
Proechimys cayennensis goeldii, [Ellerman], 1940, The families and genera of living rodents, Brit. Mus. (Nat. Hist.), 1:121.
Type locality.—Santarem, Santarem, Pará, Brazil. Type: British Museum (Nat. Hist.), no. 5.1.25.6, adult female; presented by Dr. E. A. Goeldi.
Range.—Margins of the Amazon, between Jamundá and Tapajoz rivers.
Diagnosis.—Upper parts Ochraceous-Tawny; wide across zygomata; nasals of moderate length; incisive foramen long and narrow; vomerine sheath complete but maxillary part slender; first and second upper molars with four counterfolds.