Order PR0CELLARIIF0RME8 
No. 121. 
Family DIOMEDEIDjE. 
THALASSOGERON CAUTUS CAUTUS. 
SHY MOLLYMAWK. 
(Plate 100.)* 
Diombdea cauta Gould, Proc. Zool. Soc. (Lond.) 1840, p. 177, 1841; Bass Strait, 
Australia. 
Diomedea cauta Gould, Proc. Zool. Soc. (Lond.) 1840, p. 177, 1841 ; id.. Birds Austr., 
Vol. VII., pi. 40, 1844 ; id., Handb. Birds Austr., Vol. II., p. 434, 1865 ; Coues, 
Proc, Acad. Nat. Sci. Philad. 1866, p. 183; Ramsay, Proc. Linn. Soc. N.S.W., 
Vol. II., p. 202, 1877 ; id.. Tab. List Austr. Birds, p. 23, 1888 ; Le Souef, Ibis 1895, 
p. 413 ; Ashworth and Le Souef, Viet. Naturalist, Vol. XI., p. 139, 1895 ; Buller, 
Suppl. Birds New Zeal., Vol. I., p. 153, 1905, 
Tlialassogeron cautus Ridgway, Man. N. Amer. Birds, p. 53, 1887 ; Salvin, Cat. Birds Brit. 
Mus., Vol, XXV., p. 449, 1896 ; Campbell, Nests and Eggs Austr. Birds, p. 929, 
1901 ; Hall, Key Birds Austr., p. 96, 1906 ; Reichenow, Deutsche Siidp. Exp., 
Vol. IX., Zool., p. 476, 1907 ; Mathews, Handl. Birds Austral., p. 19, 1908 ; Godman, 
Monogr. Petrels, p. 348, 1910 ; Littler, Handb. Birds Tasm., p. 187, 1910 ; Arm- 
strong, Emu, Vol. IX., p. 155, 1910. 
Diomedia cauta cauta Mathews, Nov. Zool,, Vol. XVIII., p. 205, 1912, 
Distribution. Seas of the Southern portion of Austraha. 
Adult male. Upper-back slate-grey, with white bases and pale margins to the feathers ; 
scapulars ash-brown, white only at the extreme base ; wing-coverts dark brown 
with white bases ; the smaller coverts showing pale edges ; primary-coverts and 
primary-quiUs dark brown, the latter with white shafts and white on the inner webs ; 
secondaries also dark brown, with the basal portion of the inner webs white ; tail- 
feathers hoary -grey with white shafts ; a narrow eyebrow and a spot in front of the 
eye black, becoming pale towards the base of the bill, a patch behind the eye 
including the ear-coverts washed with plumbeous-grey ; head and neck all round 
white, as also the under surface of body, including the axillaries, under wing-coverts 
white, the marginal ones blackish; “Bill bluish horn, lower mandible darker, 
upper mandible with a narrow belt of black and on each side of the nostrils ; base 
of lower mandible with a belt of orange reaching to the corner of the gape ; iris 
brown; feet bluish-white” (J. Gould). Total length 987 mm.; culmen 137, wing 
590, tail 204, tarsus 86, 
* The Plate is lettered Diomedea cauta. 
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