260 Bulletin American Museum of Natural History. [Vol. XXXIV, 
below than either estwans or gilvigularis. Upperparts finely grizzled yellow- 
ish and black, giving an olivaceous gray effect; underparts pale ochraceous 
buff, much paler on throat; tail as in estuwans but paler; no postauricular 
patches. | 
Total length (type, collector’s measurements), 343 mm.; head and 
body, 178; tail vertebrae, 165; hind foot, c. u., 47. The two topotypes are 
smaller and not quite mature. Skull, type (from Thomas, /. c.), total length, 
45; zygomatic breadth, 27.5; interorbital breadth, 16; nasals, 10.5 X 6.2; 
diastema, 11.5; maxillary toothrow, 6.8. 
Two adult females from Serra do Lua (near Boa Vista, Amazonas), 
total length, 355, 362; head and body, 164, 172; tail vertebra, 181, 190; 
hind foot, c. u., 46, 46. Skulls of the same specimens, total length, 44.7, 
45.6; zygomatic breadth, 26, 25.8; interorbital breadth, 15, 15.8; breadth 
of braincase, 21, 20.5; length of nasals, 11, 11; diastema, 11, 11; maxillary 
toothrow, 7, 7. | 
Specemens examined, 5.— British Guiana: Kanuka Mountains, 3, 
type and topotypes (Br. Mus.). Brazil: Serro do Lua (near Boa Vista, 
Amazonas), 2 (Field Mus.). 
Remarks.— This is a pale form, intermediate between G. westuans estuans 
and G. estuans gilvigularis. , 
Guerlinguetus estuans venustus subsp. nov. 
Type, No. 36155, 2 ad., Boca Sina (altitude 440 ft.), Rio Cunacunumd, (southern 
base of Mount Duida), Venezuela, March 19, 1913; Leo E. Miller. 
Pelage and coloration as in G. estuans estuans, but size smaller. Upperparts 
grizzled rufous and black, the hairs blackish annulated narrowly with rufous at the 
tip; underparts orange, chin and throat ochraceous buff; tail coarsely grizzled orange 
and black, both above and below, the tip black with the ends of the hairs orange; 
limbs externally like the upperparts, internally like the ventral surface; ears small, 
clothed with short orange-tipped hairs; postauricular patches absent. | 
_ Total length, —; head and body, 165; tail, — (imperfect); hind foot, c. u., 43. 
Skull, total length, 42.5; zygomatic breadth, — ; interorbital breadth, 15; breadth 
of braincase, 21; length of nasals, 14; diastema, 11; maxillary toothrow, 7.3. 
Represented only by the type, a young adult female. 
This form, in its coloration, closely resembles specimens of true wstuans 
from the coast region of British Guiana, and hence is very unlike the pale 
guvigularis of the lower Rio Caura region and the middle Rio Orinoco. 
The only known specimen has the tail imperfect, and the skull is slightly 
broken. 
