URIA. 213 



ful oars in their submarine flight ; in all the pen- 

 guins the feathers of the wings are very short, scale- 

 like and adpressed. From the Divers we are very 

 easily led to the Auks by means of the Guillemots, 

 forming the 



GENUS URIA, Brisson. Generic characters. Bill 

 of mean length, compressed, pointed; maxilla 

 bending to the tip, which is notched; mandible 

 with a gentle ascending angle; nostrils basal, 

 lateral, half concealed by feathers ; wings rather 

 short, accuminated, first quill longest; legs 

 placed far behind, tarsi short, somewhat com- 

 pressed ; feet small, palmated, outer and centre 

 toe equal in length, claws falcate, sharp ; hal- 

 lux wanting. 



Types. U. troile, Irunnickii, &c. Europe, North- 

 eastern Asia, North America. 



Note. Breed gregariously on precipitous rocks : 

 summer and winter plumage slightly different, 

 variation confined to the head and neck ; eggs 

 disproportionally large. 



