PKOCELLABIID^ PEOCBLLABIA 465 



rounded, consisting of twelve feathers ; tarsus slightly longer than 

 the middle toe and claw and about half the length of the femur, 

 covered in front by hexagonal scutes ; claws sharp and compressed ; 

 two caeca on the intestine ; plumage sooty-black. 



This genus contains only two species, the well-known Stormy 

 Petrel, found throughout the greater part of the Atlantic, and a 

 second species apparently confined to the neighbourhood of the 

 Galapagos Islands ia the Pacific. 



Pig. Ii5. — Left foot of Piocellaiia pelar/ica. 



782. Procellaria pelagica. Storm Petrel. 



Procellaria pelagioa, Linn. Syst. Nat. 12th ed. i, p. 212 (1766) ; Ourney, 



in Andersson's B. Bamaral. p. 351 (1872) ; Sliarpe, ed. Layard's B. 



S. Afr. p. 765 (1884) ; Salvin, Cat. B. M. xxv, p. 343 (1896) ; Shelley, 



B. Afr. i, p. 166 (1896). 

 Thalassidroma oceanioa {nee Kuhl), Layard, B. S. Afr. p. 359 (1867). 

 Thalassidroma pelagica, Dresser, B. Eur. viii, p. 497, pi. 613, fig. 2 



(1874). 

 Hydrobates pelagicus, Beichenotv, Vog. Afr. i, p. 34 (1900). 

 " Mother Carey's Chicken '' of Sailors. 



Description. Adult. — General colour sooty-black, a little paler 

 on the under surface ; upper tail-coverts white tipped with black ; 

 under tail-coverts and tail-feathers with concealed white bases, but 

 the shafts black throughout ; a small patch of whitish on the under 

 wing-coverts ; bill and legs black. 



Length about 7'5 ; wing 4-5 ; tail 2-0 ; culmen 0-5 ; tarsus 0-88 ; 

 middle toe 0-71. 



The sexes are alike, and the young resembles the adult but is 

 of a paler brown. 



30 VOL. IV. 



