548 THE AMERICAN NATURALLIST. [Vor. XXXV. 
There is a great deal to be said in favor of this classification, 
and it can be largely supported when the osteological char- 
acters presented on the part of the bird forms representing 
these various families are taken into consideration, as I have 
already demonstrated in my memoirs in the Journal of Anatomy 
and Phystology of London cited in a former paragraph of this 
paper. Dr. Sharpe is also quite correct when he places, as he 
does, in The Hand-List of Birds these three orders between 
the Charadriiformes upon the one hand and the Sphenisci- 
formes upon the other. 
Synopsis of the Osteological Characters of the Alce. 
I. The superior mandible of the skull varies in its mor- 
phology. It may have its anterior portion elevated, convex, 
prominent, laterally compressed, and cultrate, terminating in 
a sharp hook, as in Alca, Fratercula, and Lunda; or, the 
superior mandible may not be hooked, the foregoing charac- 
ters remaining the same, as in Cyclorrhynchus; or, it may 
taper gradually to a point, with the culmen roundly convex 
and not modified, as in Synthliborhamphus, Brachyrhamphus, 
Cepphus, and in Uria; or, finally, it may be broad at its base, 
and shortened, while its general characters remain the same. 
2. With regard to the supraorbital glandular depressions, 
they may be entire, the upper orbital rim being finished off 
with an osseous emargination ; and this associated with the 
crotaphyte fosse either reaching the supraoccipital prominence 
or encroaching upon its summit, as in Alca and in Uria ; or, 
the supraorbital glandular depressions may not be entire, the 
upper orbital rim being absorbed, producing wing-like post- 
frontals, and these characters associated with lateral crotaphyte 
fossæ, as in Fratercula, Lunda, Simorhynchus, Ptychorham- 
phus, Synthliborhamphus, Brachyrhamphus, and Cepphus. (It 
is in Brachyrhamphus that the crotaphyte fossz are lateral.) 
3. The extent to which the zwzerorbital septum and the 
anterior wall of the brain-case ossifies varies greatly with 
age and is therefore an unreliable character. There is always 
more or less bony deficiency in these parts in the Alce. 
