440 DIOMEDEID^. 



Family IV. DIOMEDEID^. 



Keij to the Qenera. 



■a. Sides of the mandible without longitudinal 

 sulcus ; tail short, rounded. 

 a'. Base of the culminicorn wide, joining the 



{)roximal end of the dorsal edge of the 

 atericorn 1. Diomedea, p. 440. 



b'. Base of the culminicorn narrower, divided 



hy membrane from the latericorn 2. Thalassogeron, 



h. Sides of the mandible with a deep longitudinal [p. 449. 



sulcus ; tail long, cuneate 3. Phcebetria, p. 453. 



1. DIOMEDEA. ^ 



Type. 



Diomedea, Linn. Syst. Nat. i. p. 214 (1766) ; Bjj. 



Consp. Av. ii. p. 184 (1855) ; Coues, Pr. Ac. Phil. 



1866, p. 175 ; Forbes, Voy. 'Chali:, Zool. iv. pt.xi. 



p. 42 &c. (1882) D. exulans. 



Phoebastria, Reich. Syst. Av. p. v (1852) D. albatrus. 



Thalassarche, Reich. Syst. Av. p. v (1852) D. melanophrys. 



Range. Southern Ocean and North Pacific Ocean, 



Key to the Species. 



a. Larger : bill very strong ; interscapidar region 

 and middle of the back white. 

 a! . Head white. 



a'. Upper back with narrow transverse dark 

 lines ; wing-coverts dark slaty-black, the 

 smaller coverts becoming nearly white 

 towards the edge of the wing ; exposed 

 portion of the primaries beneath black. 



Young brown, the face white exulans, p. 441. 



b" . Upper back without transverse dark lines ; 

 longer scapulars very irregularly marked 

 with dark grey ; wing-coverts dark grey, 

 irregularly mottled towards the edge 

 with white ; exposed portion of prima- 

 ries beneath black. Young white, from 



the downy nestling regia, p. 443. 



c". Upper back without transverse dark bands, 

 the scapulars alone faintly banded ; wing- 

 coverts nearly white, the middle coverts 

 only variegated with black ; exposed 

 portion of the primaries beneath with a 

 large white patch on the inner web .... chionoptera, p. 443. 



b'. Head buff albatrus, p. 444. 



h. Smaller ; bill more slender. 



c'. Interscapular region and middle of the back 

 sooty-black or brown. 

 d". Abdomen dark, closely freckled with 



white iri'orata, p. 445. 



e" . Abdomen sooty-brown nigripes, p. 445. 



/". Abdomen white immutabilis, p. 446. 



