448 DUSKY GROUS. 
TETRAO oBscuRUs, Dusky Grovus, Ch. Bonaparte, Amer. Ornith. vol. iii pl. 18.—/d. 
Synopsis of Birds of United States, p. 127.—Richards. and Swains. Fauna Bor.- 
Amer. vol. ii. p. 344. 
Dusxy Grovs, Nuttall, Manual, vol. i. p. 666. 
Adult Male. Plate CCCLXI. Fig. 1. 
Bill short, robust, slightly arched, rather obtuse, the base covered 
by feathers. Upper mandible with the dorsal line convex and declinate, 
the ridge convex, the sides convex, the edges sharp and overlapping, the 
tip thin-edged and rounded; lower mandible with the angle long and 
wide, the dorsal line ascending and convex, the ridge broad, the sides 
convex, the edges inflected, the tip rounded. Nostrils in the fore part 
of the large and feathered nasal depression, roundish. 
Head small, ovate ; neck of ordinary length; body large and full- 
Feet stout, of moderate length; tarsus short, feathered ; toes stout ; 
the first very small, the lateral about equal, and much shorter than the 
third ; the anterior toes connected by basal scaly membranes, partially 
covered with feathers ; all with broad and short scutella, margined, but 
searcely pectinate, the lateral scales not being prominent. Claws rather 
large, arched, compressed, rather obtuse. 
Plumage full, soft, rather blended, the feathers broad and rounded. 
A bare papillate space around the eye. Feathers on the upper part of 
the head narrow and elongated. Wings rather short, convex, much 
rounded ; the quills very strong ; the third longest, the fourth next, the 
third and sixth about equal, as are the first and seventh. Tail large. 
of ordinary length, rounded, of twenty feathers, which are broader to- 
ward the end, and abruptly rounded. 
Bill brownish-black, lighter at the base. Iris dark hazel. Toes 
bluish-grey, claws wood-brown. Papillar space around the eye vermi- 
lion. Upper parts blackish-brown, the wings lighter. The elongated 
feathers on the head greyish-brown ; the hind neck minutely undulated 
with bluish-grey ; the scapulars, inner secondaries, and smaller wing- 
coverts also minutely undulated with grey and brownish-red, and most 
of the latter with a small greyish tip ; the rump and upper tail-coverts 
obscurely undulated with grey. Alula, primary coverts and quills, 
clove-brown, the secondaries bordered and tipped with yellowish-grey ; 
the primaries mottled with grey on their outer webs. The tail is 
black. The sides of the head, fore part and sides of the neck, and fore 
part of the breast greyish-black ; the lore and throat are barred with 
ots 
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