Genus —PROMERGUS ( australis). 
(Plate 94.) 
Promergus Mathews and Iredale, Ibis, 
July, 1913, p. 410. Type (by original 
designation) .. .. .. . . Mergus australis (Hombron and 
Jacquinot). 
Merganserine birds with long, slender bills, “ toothed ” instead of having 
lamellae, as the ducks have, pointed wings, short tails and thin compressed 
tarsus. 
Bill long and slender, depth at the frontal feathers about one-fourth the 
length ; the culmen flattened at the base, rounded, dished and culminating in 
a large nail which overlaps the lower mandible. Nostrils operculate, linear 
and placed in a groove about a third from the base, almost on the cutting-edge. 
Interramal space narrow and feathered. The both mandibles have widely 
set “teeth ” pointing backwards. Wing pointed, first primary longest, the 
second a little shorter, the tliird about a quarter of an inch shorter than the 
second and the fourth about as much shorter than the third. Tail of short, 
stiff feathers. Tarsus equal to the inner toe in length, thin and compressed, 
scaled in front, reticulated behind. Hind-toe raised and with a large lobe 
which extends to the end of the toe. Outer toe and claw equal in length to 
the middle toe and claw. The head has a single crest and the colour-pattern 
is the same in the sexes. 
In Mergus Linne, Syst. Nat., 10th ed., p. 129, Jan. 1st, 1758, type Mergus 
castor = Mergus merganser L., the sexes have a different colour-pattern and the 
depth of the bill at the frontal feathers is more than a third its length. Gray, 
Gen. Birds, Vol. III., pi. 170, for head, wing and foot of the type of the genus 
Mergus. 
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