“Tree-Ducks” of the genus Dendrocygna. 15 
I have made several attempts to obtain the skulls of other 
species of Dendrocygna in order to ascertain if this completed orbital 
ring was present in them, but for the lack of means I have been 
unable to command such material.!) Nevertheless I have, in one 
instance, been most courteously assisted in this matter, — I refer 
to the data sent me by R.H. Burxe, Esqr. of the Royal College of 
Surgeons of England, who, in reply to a letter of mine, wrote me 
on the 4th of November, 1912, and sent me a sketch of the orbital 
ring as it obtained in two specimens of Dendrocygna javanica at the 
Royal College. The sketch is of No. 1433 of that extensive collection. 
Mr. Burne states that “in D. javanica the osseous periphery of the 
orbits is complete”. It is clear from his lucid sketch, which I very 
much regret I cannot reproduce here, that it agrees, in all essential 
particulars, with the orbital ring in D. bicolor and D. autumnalıs. 
Mr. Burne also sent me some helpful sketches of the sterna in the 
ducks with notes about them, and these latter I will introduce 
further on in this contribution. I am greatly indebted to him for his 
prompt response to my inquiries, and I have pleasure in acknowledging 
it here. 
When I was examining the skins of the various species of the 
genus Dendrocygna at the U. S. National Museum, I could sometimes 
feel the lower arc of this bony ring of the orbit just below the eye 
by means of a little pressure with my finger; so I think it is safe: 
to predict here that it will be found to be the case, in all true 
representatives of this genus, that the orbital ring is complete, — 
fully as much so as in the American forms of the group. 
In the Snow Goose (Chen h. hyperboreus), which has a skull very 
unlike that part of the skeleton in Dendrocygna autumnalis, — Or 
probably any of the Tree-Ducks for that matter, — no such orbital 
ring exists; in fact, the apex of the lower process of the lacrymal 
is directed forwards instead of backwards, which is very good 
The space between the upper edges of the orbits much wider than in 
Tadorna; orbits very small.“ And, although in the Supplement he gives 
a full-page Plate of the skeleton of D. arcuata, in which the orbit has 
been drawn by his artist as completely encircled by bone, EyTon himself 
did not seem to be aware of the fact. 
1) One American dealer in fancy fowls asked 36 $ per pair for 
living specimens of Dendrocygna viduata. I will say, however, that he 
has promised me the body of the first specimen of this species that dies 
on his extensive game preserves. 
