The Zoologist— Februarv, 1870. 2005 



class of animals in which the recognition and definition of subordinate 

 groups is peculiarl}- difficult. 



The natural place of the family in our ornithotaxis appears as 

 definite as the characters which separate its forms from other birds. 

 By common consent, the Alcidae are regarded as next to the lowest of 

 birds. The degradation of the type or ideal bird which the auks 

 represent is only carried further in one family — the Spheniscidse. 

 From the latter, which is at the bottom of the scale, we ascend one 

 step to Alcidae; another brings us to the Colymbidae and Podicipidae. 

 These four families constitute the order Pygopodes, or the Brachy- 

 plerous Natatores. The position occupied by the auks in this order is 

 so evident as not to admit of question. 



It is only necessary to allude to the wings of the Spheniscidan, 

 without dwelling upon the point, to separate this family from the 

 auks. The tetradactylous feet of the other two families distinguish 

 them with equal facility. Auks are brachypterous, brachyurous, 

 tridactylous Natatores, with lateral nostrils. This expression is a 

 perfect diagnosis. 



The auks are confined to the northern hemisphere. Some repre- 

 sentatives have been found as far north as explorers have penetrated. 

 The great majority live in more temperate latitudes. A more or less 

 complete migration takes place with most species, which stray south- 

 ward, sometimes to a considerable distance, in the autumn, and return 

 north again to breed in the spring. A few species appear nearly 

 stationary. The most southern recorded habitat of any member of 

 the family is about latitude 21® N., on the Pacific coast of North 

 America, but this is rather exceptional. The species are very un- 

 equally divided between the two oceans. The Atlantic has but few 

 representatives compared with the Pacific. On the northern coasts of 

 the latter the family reaches its highest development: the greatest 

 number of species, of the most diversified forms, are found there, 

 though the number of individuals of any species does not surpass that 

 of several Atlantic species. Comparatively few species are common 

 to both oceans. All the members of the family are exclusively 

 marine.* They are decidedly gregarious, particularly in the breeding 

 season, when some species congregate in countless numbers. Usually 

 one, often two, rarely if ever three eggs are laid, either upon the bare 

 rock or ground, or in crevices between or under rocks, or in burrows 



* Uiia grjUe is found on the southern shoves of Hudson's Bay ; hut tliis fact cuu 

 hardly furnish au exception to the statement. 



