362 BRITISH BIRDS. 



Family ALCID.^, or AUKS. 



The Auks form a small but well-defined family, probably nearest related 

 to the Divers. When the study of birds has sufficiently progressed to 

 make the grouping of Families into Orders a possibility, it is not improbable 

 that the Auks, the Divers, and the Plovers may find themselves grouped 

 round the more highly developed Gulls and Petrels. Forbes associated 

 them with the Gulls and Plovers ; Selater places them in an order with the 

 Grebes and Divers; and Gadow places them between the Gulls and Divers. 

 In the arrangement of the bones of the palate the Auks are schizognathous, 

 and were placed by Huxley in a family which he called Cecomorphse, and 

 which contained also the Gulls, the Petrels, and the Divers. In their 

 pterylosis the Auks resemble the Divers, the Grebes, and the Penguins, 

 though having well-marked characters of their own. There are two notches 

 on each side of the posterior margin of the sternum in the Auks, but the 

 inner pair are often closed at the entrance. 



The Auks moult completely in September, and change their small 

 feathers in March from winter to summer plumage. The young are born 

 covered with down, and can swim almost at once. The first plumage is 

 assumed in a month or more, and is moulted in the first spring iiito a 

 plumage very closely resembling that of the adult. 



The Auks have no hind toe ; the feet are webbed and placed very far 

 back; the tarsus is very short and covered with small hexagonal scales, 

 which are generally enlarged in front into bi'oad scutellae; but in some 

 species the scutellation is very incomplete. The wings and tail are short, 

 and the bill is very variable in shape. 



This family is a very small one and only contains about a score 

 species. It may be regarded as circumpolar ; but many of the species are 

 confined to the Pacific coasts of the Arctic regions. 



Genus FRATERCULA. 



The Puffins were included by Linnaeus in the genus Alca; but in 1760 

 Brisson, in his ' Ornithologia,' vi. p. 80, provided the genus Pratercula 

 for their reception. The Common Puffin, F. arctica (being the Fratercula 

 fratercula of Brisson) , is the type. 



