Part 14

Specimens examined.--Total number, 21, from Brazil, Pará, as follows: Porto de Moz, Tauarí, right bank of Tapajoz, approximately 85 kilometers south of Santarem, 20 (19 MCZ, 1 CNHM); Obidos, Obidos, 1 (MCZ).

=Proechimys guyannensis nesiotes= subspecies nova

Type locality.--Ilha de Manapirí, Rio Tocantins, Pará, Brazil. Type: Chicago Natural History Museum, no. 19496, adult male; collected on 9 December, 1910, by Dr. Emilia Snethlage; original number, 12.

Range.--Known only from the type locality.

Diagnosis.--Aristiforms wide and stiff; general color on upper parts Ochraceous-Orange; incisive foramen long, with parallel borders; vomerine sheath complete and thick; p4 with four counterfolds, remaining molariform teeth with three counterfolds.

Pelage.--Aristiforms on middorsal region: Gray basally, gradually blackening toward tip; total length, 18 to 19 mm; maximum width, 0.9 mm. Setiforms on middorsal region: Gray basally, gradually blackening toward tip but interrupted by Ochraceous-Orange, subapical zone 4 mm long; total length 16 to 19 mm; maximum width, 0.06 mm. Setiforms on outer thighs: Whitish basally, gradually becoming gray and blackish toward tip but interrupted by Ochraceous-Buff, subapical zone 3 mm long; total length, 13 to 15 mm; maximum width, 0.03 mm.

Skull.--Of medium size; rostrum short; nasals pointed posteriorly; postorbital ridges extending caudad across anterior fifth of parietals; zygomatic arches strong; jugal with process in posterior part of masseteric fossa; postorbital process of zygoma involving mostly squamosal; incisive foramen elongate, narrow (5 x 2.3 mm), and parallel sided; posterior margin of incisive foramen approximately 3 mm anterior to premolars; margins of foramen raised to form ridges; vomerine sheath complete, of almost uniform width and set deeply in foramen; mesopterygoid fossa extending forward as far as centers of third molars; bullae of medium size and inflated.

Teeth.--Upper molariform teeth with three counterfolds; p4 with four counterfolds; m1-3 with three counterfolds.

Comparison.--From P. g. oris, nesiotes differs in: Aristiforms conspicuously wider; incisive foramen shorter and narrower, with borders parallel instead of posteriorly constricted; posterior margin of incisive foramen farther from premolars; p4 with four, instead of three, counterfolds; lower molars with three instead of two counterfolds. From P. g. leioprimna, nesiotes differs in: Incisive foramen with parallel borders instead of oval; p4 with four instead of three counterfolds; m3 always with three instead of two counterfolds.

Remarks.--Dr. E. Snethlage mentions the type as having been collected at night in the forest.

Specimens examined.--Total number, 8 (MCZ, CNHM, MN), from Brazil, Pará, Tocantins River, Ilha de Manapirí.

=Proechimys guyannensis leioprimna= subspecies nova

Type locality.--Cametá, left bank of Tocantins River, near its mouth, Cametá, Pará, Brazil. Type: Chicago Natural History Museum, no. 19503, adult female; collected on 21 January, 1911, by Dr. Emilia Snethlage; original number, 35.

Range.--Known only from type locality but probably extending westward toward Xingú River.

Diagnosis.--Aristiforms wide and stiff; general color on upper parts Ochraceous-Orange, incisive foramen moderately long; oval; vomerine sheath complete; all molariform teeth with three counterfolds, except lower, third molar which has only two.

Pelage.--Aristiforms on middorsal region: Gray basally, gradually blackening toward tip which is extended as a short filament; total length, 19 to 21 mm; maximum width, 0.8 to 1 mm. Setiforms on middorsal region: Whitish basally, gradually blackening toward tip but interrupted by Ochraceous-Orange, subapical zone 2 to 3 mm long; total length, 17 to 20 mm; maximum width 0.1 mm. Setiforms on outer thighs: Whitish basally, becoming gradually gray and then blackish toward tip but interrupted by Ochraceous-Buff, subapical zone; blackish tip short; total length 13 to 15 mm; maximum width 0.06 mm.

Skull.--Of medium size; rostrum relatively short; nasals with posterior borders rounded; postorbital ridges extending across anterior fourth of parietals; zygomatic arches moderately strong; postorbital process of zygoma involving both jugal and squamosal; incisive foramen of medium length (4 to 5 mm) and narrow (about 2.5 mm), oval and extending caudad to a plane approximately 2 mm anterior to premolars; vomerine sheath complete, with premaxillae forming approximately anterior 3/4 of sheath; maxillary part of sheath short but well-developed; mesopterygoid fossa extending forward as far as centers of third molars; bullae of medium size but well-inflated.

Teeth.--Upper molariform teeth with three counterfolds. Lower molariform teeth with three counterfolds, except third molar which has only two.

Comparison.--From P. g. oris, leioprimna differs in: conspicuously wider aristiforms; shorter and narrower incisive foramen; lower molariform teeth with three counterfolds (except m3 with only two), instead of lower molars with only two counterfolds. Differences from P. g. nesiotes are given in the account of that subspecies.

Remarks.--The paratype was collected in an "igarapé," depression usually invaded by the river waters; the paratype, collected on 18 January, 1911, had two large embryos.

Specimens examined.--Total number, 4 (2 CNHM, 2 AMNH), from Brazil, Pará, Cametá.

=Proechimys guyannensis oris= Thomas

Proechimys oris Thomas, September, 1904, Ann. Mag. Nat. Hist., 14 (ser. 7): 195; Thomas, 1905, Ann. Mag. Nat. Hist., 15 (ser. 7):587; Thomas, 1912, Ann. Mag. Nat. Hist., 9 (ser. 8):89; Tate, 1935, Bull. Amer. Mus. Nat. Hist., 68:400; Osgood, 1944, Zool. Ser. Field Mus. Nat. Hist., 29:199.

Proechimys cayennensis oris Ellerman, 1940, The families and genera of living rodents, Brit. Mus. (Nat. Hist.), 1:121.

Type locality.--Igarapé-assú, E. F. B., near Belem, Igarapé-assú, Pará, Brazil. Type: British Museum (Nat. Hist.), no. 4.7.4.78, old male; collected on 6 March, 1904, by Alphonse Robert; original number, 1818.

Range.--Probably most of the region on south bank of Amazon River, between Tocantins (west) and Gurupí River (south).

Diagnosis.--Aristiforms narrow but somewhat stiff; color on upper parts Ochraceous-Orange; incisive foramen long and wide, conspicuously constricted posteriorly; posterior margin of incisive foramen close to plane of premolars; vomerine sheath complete but maxillary part threadlike; upper molariform teeth and lower premolar with three counterfolds; lower molars with only two counterfolds.

Pelage.--Aristiforms on middorsal region: Gray basally, gradually blackening toward tip, which is extended as a filament; total length, 16 to 17 mm; maximum width, 0.6 to 0.7 mm. Setiforms on middorsal region: Gray basally, gradually becoming blackish toward tip but interrupted by Ochraceous-Orange, subapical zone 2 to 4 mm long; total length, 18 to 20 mm; maximum width 0.06 mm. Setiforms on outer thighs: Whitish basally, gradually becoming blackish toward tip but interrupted by Ochraceous-Buff, subapical zone; total length, 15 to 16 mm; maximum width, 0.04 mm.