TUBINAEES 455 



777. Stercorarius pomatorhinus. Pomatorhine Skua. 



Lestris pomarina, Teinm. Man. cl'Orn. p. 514 (1815). 



Stercorarius pomarinus, Gm-ncy, in Andersson's B. Damaral. p. 357 



(1872) ; Beichenow, Vog. Afr. i, p. 38 (1900). 

 Stercorarius pomatorhinus, SJiarjye, ed. Layard's B. 8. Afr. p. 695 



(1884); Sivinburnc, P. B. Phys. Soc. Edin. ix, p. 200 (1886); 



Scmnders, Cat. B. M. xxv, p. 322 (1896) ; Shelley, B. Afr. i, p. 165 



(1896). 



Description. Adult. — Eesembling S. crepidatus but larger ; 

 the central tail-feathers are broad, rounded at the end, project 

 about four inches in the adult and are twisted vertically ; the 

 acuminate feathers of the neck are white edged with warm straw 

 yellow. 



Bill horn brown ; legs reddish-black. 



Length 21-0 ; wing 14*25 ; tail about 5*25 ; with central rectrices 

 up to 9"25 ; culmen 1-7 ; tarsus 2-1 ; middle toe and claw 2-0. 



Distribution. — This is an Arctic bird, breeding chiefly in the 

 Arctic regions of both the Old and New Worlds north of 70° ; 

 during the northern winter it ranges southwards to North Australia, 

 Peru and South-west Africa. 



Within our limits it has been procured in Walvisch Bay by 

 Andersson ; one of the two examples obtained by him is now 

 in the British Museum. Mr. S. Swinburne states that he once 

 observed, but did not obtain, a Pomatorhine Skua in 32° S. lat. 

 16° E. long, about 100 miles off the west coast of the Colony. 



Order XVIII. TUBINARES. 



The members of this Order can be at once distinguished from 

 all other birds by their nostrils, which open in the form of tubes, 

 either conjoined on the culmen or separate on the sides of the 

 mandibles; in addition to this the three anterior toes are always 

 completely webbed and the hallux when present is small, consisting 

 of only one phalanx ; an aftershaft is present and the rectrices vary 

 in number from twelve to sixteen. 



The skull is schizognathous and holorhinal; the fifth cubital 

 remex is absent ; the oil gland is tufted ; there are two carotids and 

 the Garrodian thigh-muscles vary in the different families but the 

 femoro-caudal and semitendinosus are always present. 



