SOOTY TERN. 



547 



inches, and extending one inch beyond the end of the 

 tail, but in the adult bird the outside tail-feathers on each, 

 side extend for two inches beyond the ends of the closed 

 wings, giving a length of seventeen inches to the fully- 

 adult bird ; the leg and middle toe equal in length, each 

 measuring one inch. 



In the fully-adult bird also the colours are more pure 

 and decided. 



