4 M NATATORES. 



trionatis, (Lat. northern,) is another species, breeding from New- 

 foundland northwardly. Length twenty-five inches. 



The GREBES, (Podiceps.) have been variously placed by dif- 

 ferent naturalists. De Kay includes them with the COOTS, in a 

 separate order, Lobipedes, (Lobe- footed,) and ranks them imme- 

 diately before the Swimmers. We have followed Cuvier and 

 others, in placing them with the Swimmers, and in the present 

 family. Among the species are the HORNED GREBE, P. cornu- 

 tus, (Lat. horned,) in length fifteen inches; common to Europe 

 and America, and known by the names Dipper, Water-Witch, 

 &c. ; the CRESTED GREBE, P. cristatus, in length nineteen inches; 

 commonly found in secluded ponds and lakes in the interior, but 

 also seen on the sea-coast. It ranges from Mexico to 680 N. L. ; 

 is found also in Europe ; the RED-NECKED GREBE, P. rubricoHis, 

 (Lat. red-necked,) not quite so long as the preceding, and scarcely 

 seen South of New York. 



THIRD FAMILY. AUKS. 

 Alcida, (Lat. alca, alk or auk.) 



The birds of this family, have a structure which pre-emi- 

 nently adapts them to an aquatic life, and are, in their resorts and 

 habits, exclusively maritime. The beak in these birds varies 

 in length, and is more or less compressed ; both mandibles are 

 much curved and notched ; the nostrils are almost entirely closed 

 by a naked membrane ; the feet small and entirely webbed ; the 

 legs short and placed far back, so that, in sitting, these birds assume 

 an erect position ; the tail has sixteen small feathers. In moving 

 under water, the Auks make no use of their feet, but hold them 

 out behind, as the Waders do theirs in flying, and use their short 

 wings in the manner of fins, so that they may be said to fly be- 

 neath the surface. " Their movements, under water, precisely 

 resemble those of the Dyticida, or Common Water-Beetles; the 

 principal motion being more or less vertical, instead of horizontal 

 as in the Grebes and Loons; they are, therefore, together with 

 the distinct group of Penguins, the most characteristic divers of the 

 class." Their food, obtained by diving, (an operation in which 

 they are assisted by their wings as well as their feet,) consists 

 of small fishes, crustaceans, and other marine animals. The 

 Auks are frequently seen in immense numbers on rocky islets, 

 and precipitate cliffs that overhang the sea, on the shelves and 

 edges of which they lay their eggs, one only being deposited by 

 each bird. The female, while sitting in an erect, position, keeps 

 the egg between her feet for the purpose of incubation. Many 



