392 



STRIGIN^:. 



teen ; the filaments of the outer web of the outermost quill 

 usually separated at the end and recurved. The tail, always of 

 twelve more or less arched feathers, varies in length, but is 

 generally short and even, or slightly rounded. 



The cranium is always short, of extreme breadth behind, 

 somewhat triangular, and of very large size ; but its bulk is in 

 a great measure produced by the separation of its two tables by 

 the intervention of numerous cells. The orbits are excessively 

 large, and separated by a bony septum, Avhich is generally com- 

 plete, sometimes thickened, and in the genus Strix more than 

 a quarter of an inch in breadth, and cellular. The superciliary 

 bone is not present as in the Falconinae, or exists merely in a 

 rudimentary state, and is never distinct. The nasal cavity is 



rather large ; that of the ear extremely so ; but not in propor- 

 tion to the external parts. The vertebrae vary in number ; 

 but there are generally twelve cervical, eight or nine dorsal, 

 twelve sacral, and eight caudal ; of which the last is usually 

 not half the size of that of the falconine birds. The ribs, 

 seven in number, are very slender. The sternum is very short, 

 small when compared with those of the Hawks or Vultures, 



