WHITE-QUILLED ROCK PIGEON. 255 
‘of quills margined with whitish, as also the feathers of the fore-neck ; the black 
throat patch scarcely indicated ; a certain amount of chestnut on the under wing- 
coverts like that of the quill-lining. 
Nest—The bare ground, under any convenient low covert—tussock or bush 
—on the plains. 
Hggs.—Clutch, two ; elliptical in form ; texture of shell fine but strong ; surface 
glossy ; white, with a slight creamy tone. Dimensions 32-34 mm. by 24. 
Breeding-season.—Practically all the year round. 
Distribution and forms —Interior of Australia only. The western form, living 
in interior districts of the North-west of Australia is much paler above and below, 
being named H. h. alisteri (Mathews), than the typical eastern H. h. histrionica 
(Gould) from the interior of New South Wales and Queensland. 
Genus PETROPHASSA. 
Petrophassa Gould, Proc. Zool. Soc. (Lond.), 1840, p. 173, July 1841. Type (by monotypy) : 
Petrophassa albipennis Gould. 
Large Ground-Doves with slender bills, very rounded wings, long rounded tail 
and very small legs and feet. The bill is formed as in the preceding genus, the 
dertrum a little more swollen, the bill itself a little more slender, the interramal 
space less feathered, the gonys a little longer and more ascending but not angulated. 
There is a small space round the eye and part of the lores naked of feathers as in the 
preceding genus but more marked. The wing is very rounded, the primaries very 
narrow, none showing any scalloping on the inner webs but the third to the eighth 
strongly incised on the outer webs ; the first is not much shorter than the second and 
is about equal to the ninth, the intervening eight being almost the same length, 
the eighth being a little less than the others. The secondaries are very long and 
broad, the longest inner secondary being equal to the outermost primary. The 
tailis composed of fourteen very broad feathers, their extremities being almost square 
and is nearly as long as the wing ; in shape it is a broad wedge, the outer feathers 
being more than half the length of the middle eight which are practically equal in 
length. The upper tail-coverts are very dense and only reach about half-way down 
the tail, the under ones being about the same length. The legs are very small ; 
the tarsus is short and thick, about the length of the culmen, and longer than the 
middle toe ; the tarsus is covered on the front with two rows of hexagonal plates, 
the back and sides being covered with minute reticulation. The toes are very 
short, the middle toe longest, the outer and inner about equal and not a great deal 
longer than the straight hind-toe; all the claws are short and blunt. 
Coloration uniform brown or grey with darker edges to all the feathers, forming 
a scalloped appearance ; primaries showing red or white bases, very noticeable. 
173. Petrophassa albipennis—WHITE-QUILLED ROCK PIGEON. 
Gould, Vol. V., pl. 71 (pt. x.), March 1st, 1843. Mathews, Vol. I., pt. 3, pl. 38, April 29th, 
1911. 
Petrophassa albipennis Gould, Proc. Zool. Soc. (Lond.), 1840, p. 173, July 1841: ‘‘ Western 
Australia’? = Wyndham, North-west Australia (East). 
Petrophassa albipennis alisteri Mathews, Austral Av. Rec., Vol. I., pt. 2, p. 28, April 2nd, 
1912: Napier Broome Bay, North-west Australia (West). 
DisTRIBUTION.—North-west Australia, Northern Territory. 
Adult female—General colour of the upper-surface rufous-brown, with pale 
edges to the feathers ; crown of the head blackish-brown, with whitish margins to 
the feathers ; neck all round, breast and sides of the face grey, with rufous-brown 
edges to the feathers ; lores and a narrow line at the base of the fore-head velvety- 
