RAZOR-BILL AUK. 233 



developed to its greatest known extent. It consti- 

 tutes the 



GENUS FRATERCULA, Brisson. Generic charac- 

 ters. Bill short, depth of the head, triangular, 

 compressed ; culmen arched, furrowed trans- 

 versely, corners of the mouth with a dilatable 

 skin ; nostrils basal, a narrow linear slit placed 

 close to edge of maxilla ; wings short, nar- 

 row, accuminate ; legs placed behind ; tarsi 

 short, feet rather small, claws hooked and 

 sharp, hallux wanting. 



Types. F. arctica. Europe, America. 



Note. Gregarious; breed in burrows, or under 

 rocks, in fissures, &c. 



