504 Mr. N. A. Vigors 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 Alca, 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 C/m, in 

 the former of which groups it has been placed by Linnaeus, 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 Pelecatiidce, 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 Alcadce ; 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 Pelecanida. 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 Linngeus. The first of these genera is divided 

 into the following generic groups ; Phalacrocorax, Briss., which 

 seems to retain the nearest affinity to the birds of the 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 



