_Teeth._--Molariform teeth large, P4-M3 averaging more than 9 mm in length. Upper molariform teeth: P4 and M3 with three counterfolds; M1 and M2 with four counterfolds each. In lower teeth, p4 with four counterfolds and each molar with three counterfolds. _Comparisons._--Differences from _P. g. steerei_ are given in the account of that subspecies. _Remarks._--Specimens from the type locality were not available. Specimens from Fazenda Paraiso, Faro, were relied upon as representative of the subspecies. These agree with the type according to Thomas (1912:89). However, the skin of the type was changed in color by preservative (Thomas, 1905:587) and the best skin he saw was from Faro (1912:89). Thomas (1920:277) applied the name _goeldii_ also to specimens from Manacaparú, a place a short distance above Manaus on the Solimões (Amazon) River and from Acajutuba, near Manaus, on the Negro River. In referring to these specimens (2 from Manacaparú and 2 from Acajutuba) Thomas (_loc. cit._) said "Five molar laminae are frequently, if not invariably, present among these specimens." He did not, however, mention whether or not the number of laminae was constant in both M2 and M3. One specimen from Acajutuba, in the collection of Museu Nacional (MN no. 1973 [M]), actually has five laminae in M3, but the specimens in the American Museum from Faro agree absolutely with Thomas' original description of _goeldii_. Osgood (1944:199) doubted that _goeldii_ was a valid species. Evidence that Osgood's doubt was unjustified is furnished by the fact that Thomas (1912:89) pointed out that his specimen from Faro agrees with the type. Likewise, my two specimens from Faro agree with the type insofar as it has been described. Thomas (1912:89) mentioned two additional skulls from the type locality which, he stated, agree with the type which was received from the Museu Goeldi, Pará. _Specimens examined._--Total number, 4, from Brazil as follows: Pará, _Faro_, Faro, Fazenda Paraiso, 2 (AMNH); Amazonas, _Manaus_, Manaus, 1 skull (AMNH); Amazonas, _Manaus_, Acajutuba, 1 (MN). _Additional records._--Total number, 7 (British Museum), from Brazil, as follows: Pará, _Santarem_, Santarem (Thomas, 1912:89; 1920:277), 3; Amazonas, _Manaus_, Acajutuba (Thomas, 1920:277), 2; _Manacaparú_, Manacaparú (Thomas, 1920:277), 2. =Proechimys semispinosus= (Tomes) [Illustration: FIGS. 33, 36. _Proechimys semispinosus liminalis_, female, MN no. 6253, Rio Quichito. Type. × 1.] [Illustration: FIGS. 34, 37. _Proechimys semispinosus amphichoricus_, male, AMNH no. 77020, Mount Duida. Type. × 1.] [Illustration: FIGS. 35, 38. _Proechimys semispinosus kermiti_, female, AMNH no. 37124, Lower Rio Solimões. Type. × 1.2 (from photograph).]