“Tree-Ducks’” of the genus Dendrocygna. 19 
and occasionally in the Mallard and Canvas-back. When entirely 
absent, its place is filled, to a slight degree, by an osseous process 
thrown off from the mesial surface of either lacrymal. Such a process 
is present in the skull of a specimen of Chen hyperboreus before me 
(No. 7360, Coll. U. S. Nation. Mus.). Nothing of the kind is ever 
found in the skull of Dendrocygna autumnalis or D. bicolor, and I 
doubt that it occurs in any other species of Tree-Duck, as I likewise 
doubt that any of the true species of that genus will be found to 
posses, even very old birds, ossified partes planae in their skulls. 
In my “Osteology of Birds,” cited above (p. 313, fig. 41) I 
state, when describing a skull of Chloephaga poliocephala, that a 
“]acrymal bone has almost completely anchylosed with the frontal 
and nasal of the same side; and at the lower extremity of this bone 
we find an ossicle, similar in every respect to the one I described 
as oceurring in the skull of Zarus argentatus. This little bone shows 
well in the figure, extending backward from the lower expanded 
portion of the lacrymal.” I do not find this minute and free ossiele 
attached to the lower end of the lacrymal in a specimen of Chloephaga 
poliocephala at hand at this writing, nor in any other skull of the 
representatives of the Anseres before me. 
The skull referred to in my “Osteology of Birds” is now in the 
State Museum of Albany, and was collectted by Surgeon THomAs 
H. Streets of the United States Navy, in the Strait of Magellan, 
many years ago. At one time, I believe I regarded this ossicle as 
the os uncinatum. PARKER had something to say on this point 
in one of his most able and classic memoirs; but I do not think he 
quite cleared the matter up. He stated that!) “In his earlier 
Paper on Alca in which the skeleton Alca torda is described ?), 
Dr. SHUFELDT mentions a little bone attached to the lacrymal, and 
which he supposes is the one called by me *“osuncinatum” 
in my Paper in the Encyclopaedia Britannica, vol. 9, art. Birds, 
p. 714. The bone referred to is, however, merely a limited ossification 
which takes place in the hind part of the coiled inferior turbinal. 
This bone in my specimens is an elegant open ring, the bony deposit 
having affected the whole coil to a short extent; it is formed in 
1) PARKER, WILLIAM KITCHEN, On the morphology of the Duck 
and the Auk tribes. „CUNNINGHAM Memoirs“, No. VI, in: Royal Irish 
Acad., 1900, p. 71, 72. 
2) in: Journ. Anat. Physiol., Vol. 23 (Vol. 3, n. s.), p. 166—171, 
tab. 7 and ibid., Vol. 23, p. 8, tab. 1. 
2# 
