WHITE-FACED STORM-PETREL. 19 



black, the latter more or less white on the inner webs towards the base ; greater 

 coverts brown with pale margins ; lower back and scapulars dark brown ; upper 

 tail-coverts grey barred with white at the base ; tail brownish -black ; fore-head, 

 lores, an irregular line over the eye, and under-surface pure white like the axillaries 

 and under wing-coverts ; thighs and lateral under tail-coverts grey, the latter with 

 white bases ; bill black, iris hazel, feet black, webs yellow. Total length 209 mm. ; 

 culmen (exp.) 17, wing 156, tail 69, tarsus 41. 



Adult female. Similar to the male, but larger in bill measurements. 



Immature. A very small, downy young shows the adult coloration to be taken 

 on with the first feathers, the only noticeable difference being white edgings to the 

 primary and secondary quills, and wavy grey and white undulating marks on 

 the upper tail-coverts and rump. 



Fully -feathered young are quite like the adult but cleaner looking, with con- 

 spicuous white edgings to the secondaries. The wing measurement is noticeably 

 less. 



Nestling. Covered with ashy-grey down above, white below. 



Nest. In a burrow. 



Egg. Clutch, one ; variable in size and shape as well as colour markings ; 

 sometimes pure white with scarcely any spots, sometimes with the larger end thickly 

 speckled with minute pale rusty spots, and at others speckled sparsely all over with 

 such spots, massed at larger end and intermingled with a few larger blackish streaks ; 

 elongately oval to subrotundately oval ; axis 35-41 mm., diameter 25-28 mm. 



Breeding -season. November to January. 



Distribution and forms. Breeding in New Zealand, southern Australia, South 

 and North Atlantic Ocean. Five forms have been separated : P.m. marina (Latham) 

 breeding on Tristan d'Acunha, Nightingale Island, etc., South Atlantic Ocean ; P. m. 

 hypoleuca (Webb and Berthelot) with a longer bill and lighter coloration above, 

 especially the ashy-grey mantle, breeding on the Great Salvage Islands, Canary 

 Islands, Cape Verde Group, etc. ; P. m. dulcice Mathews, the West Australian form, 

 with longer bill than the typical race, also lighter mantle and back, but darker than 

 preceding ; P. m. howei, the East Australian race, has the mantle and back distinctly 

 darker grey with scarcely any fuscous shade ; and P. m. maoriana Mathews, with 

 a shorter bill and the mantle, sides of neck, and upper back light brown, not grey. 



Genus FREGETTA. 



Fregetta Bonaparte, Comptes Rendus Acad. Sci. Paris, Vol. XLL, p. 1113, (Dec. 31st) 1855. 

 Type (by original designation) : Thalassidroma leiicogaster Gould. 



Cymodroma Ridgway, Mem. Mus. Comp. Zool. Harvard (Water Birds N. Amer., Vol. II.), 

 Vol. XIII., pp. 363, 418, (introduction dated March 31st) 1884. Type (by original desig- 

 nation) : T. tropica Gould. 



Small Storm-Petrels with short hooked bills, long wings, long emarginate tail 

 and long legs and short toes. The bill is short, sharply hooked, the tubes as in the 

 preceding almost half the length of the culmen ; the unguis short and sharply 

 hooked, the side slope fairly steep. The unguis of the lower mandible is correspond- 

 ingly short, the interramal space narrow and feathered. The wing has the same 

 formation as in the preceding genera. The tail is scarcely forked and is practically 

 half the length of the wing, the feathers broad. The legs are long, the exposed 

 tibia long ; the tarsal covering booted in front, and covered with reticulate scaling 

 behind ; the basal phalanges of the toes have also a smooth surface ; the outer toe 

 longest, the inner and middle being very little less ; the claws are short and com- 

 paratively broad, that of the middle toe being slightly the longest. There is still 

 only a minute hind -toe, and the anterior toes are fully webbed. 



Coloration : head and all upper surface sooty ; chest and abdomen white. 



C 2 



