504 Mr. N. À. Vicors on the Natural Affinities 
gradation of affinities between conterminous groups leads us 
back again to the point from whence we started. Some species 
of the Linnean A/ca, which M. Temminck has united under the 
generic title of Phaleris, with bills less elevated at the culmen, 
and more tapering than that of Fratercula, lead us gradually to 
the Mergulus of Ray, the little Auk of our cabinets. This genus, 
strongly and distinctively separated both from Alca and Uria, in 
the former of which groups it has been placed by Linnæus, and 
in the latter by M. Temminck, may be considered as interme- 
diate between them. It thus brings us to Uria, where the 
pointed and tapering bill, again discernible, reconducts us to 
Aptenodytes. 
The groups that compose the last family are characterized by 
having no hind toe. ‘Those of the family of Pelecanide, next in 
succession, and now before us, are distinguished by what is termed 
a syndactyle foot, the hind toe of the bird being directed to the 
front, and all the toes being united by a membrane. "These two 
families, thus separated from each other, are however brought 
into contact by the Aptenodytes of the last family, which pos- 
sesses a hind toe, but small and feeble in construction, in which 
it approaches the three-toed A/cade ; while on the other hand it 
has this member directed to the front, but without a connecting 
membrane, by which means the four toes are similarly placed 
with those of the Pelecanide. The family now before us, cor- 
responding with the ** Totipalmes” of M. Cuvier, comprises the 
whole of the groups which formed the genera Pelecanus, Phaeton, 
and Plotus, of Linnæus. The first of these genera is divided 
into the following generic groups ; Phalacrocorax, Briss., which 
seems to retain the nearest affinity to the birds ofthe last family in 
habits and appearance ; Onocrotalus, Briss., the genus so familiar 
to us as including the Pelican of the Wilderness; Sula, Briss., 
which contains our Gannet ; and Tachypetes, of M. Vieillot, the 
Frigate 
