No. 414.] POSITION OF THE SCREAMERS. 457 
of Garrod's in the P. Z. S. of 1876. His figures illustrating 
his remarks are extremely instructive, comparing as he does 
the occipital aspects of the skull of a Magellaine goose (Chæ- 
phaga magellanica), a Derbian screamer (Chauna derbiana), and 
a razor-billed curassow (Mitua tuberosa). He also gives the 
basal view of the skull of Chauna derbiana. Garrod draws 
some very careful comparisons among the several forms just 
named, and it is well worth the pains of the student of avian 
osteology and classification to read what he has to say, in the 
paper cited, in connection with the present contribution. 
With the view of throwing additional light upon the affini- 
ties of the screamers, I have compared the skeleton of the 
horned screamer, Palamedea cornuta (see plate, opposite page), 
with that of the Coscoroba swan (Coscoroba coscoroba) and the 
common wild turkey (Meleagris gallopavo) and arranged the 
principal osteological characters characteristic of each form in 
the subjoined table in a comparative way, thus supplementing 
the results already achieved by Garrod and further emphasizing 
some of the opinions arrived at by him in regard to the system- 
atic position of the screamers. 
SKULL. 
General aspect. 
Superior mandi- 
SCREAMER. 
SWAN. 
TURKEY. 
C pi ly 5 
B. 
Characteristically 
galline. 
Typically anserine. 
As in other An- 
seres and quite 
different. 
Typically galline. 
Agrees almost ex- 
actly the 
screamer: gal- 
line. 
area. 
Lacrymal bone. Very small but | Very large, with | As in the fowls 
anserine superior portion | generally, and 
elongated. very different 
Interorbital sep- | Entire. Entire. Perforated 
tum. 
Quadrates. Ansero-galline. Anserine. Galline 
Auricular open- | Galline. Anserine. Galline 
ing. 
Lateral processes | Anserine. Anserine. Fuse distally, and 
of the cranium. thus include a 
foramen. 
Palate. Desmognathous. | Desmognathous. Schizognathous. 
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