MONOGRAPH OF THE PETRELS. 



b" . Greater wing-coverts very slightly paler than 

 the other coverts ; upper tail-coverts white, 

 broadly tipped with black 



a'". Smaller; wing, 5.8-6.1 inches; middle 



toe and claw, 0.9-0.95 inch . . . . castro, p. 15 



b'". Larger ; wing, 6.3-6.7 inches ; middle 



toe and claw, 1.2-1.25 inch . . . . macrodactyla, p. 18 



b' . Upper tail-coverts not white, but sooty-black 

 like the back. 



c". Larger ; wing, 5.95-7.2 inches. 



c"'. Plumage sooty-black, including the 

 under wing-coverts. 



a 4 . Bill stout ; culmen, 0.6 inch ; 



wing exceeding 6.75 inches . . melania, p. 24 



6*. Bill slender ; culmen, 0.7 inch ; 



wing, 6.8-7.2 inches . . tristrami, p. 20 ; marlchami, p. 27 

 d'". Plumage more ashy ; bill slender ; 

 culmen, 0.6 inch ; wing, 5.7-6.2 inches 

 in length . . . . . . . . . . monorhis, p. 32 



d". Smaller; wing, 5.1-5.65 inches; greater 



under wing-coverts externally ashy . . homochroa, p. 29 



b. Upper-parts grey ; under-parts white, with a slate- 



coloured band across the fore-neck ; crown 



blackish . . . . . . . . . . . . horribyi, p. 36 



c. Upper- and under-parts entirely pale ashy-grey . . furcata, p. 38 



SUB-FAMILY II.— OCEANITIN^. 

 (Salvin, Cat. Birds Brit. Mus., XXV., p. 358.) 



Key to the Genera. 

 a. Basal phalanx of the middle toe normal, or only 

 slightly flattened, less than the remaining joints 

 and claw. 



a'. Claws sharply spatulate, not much flattened. 



a". Scutellse on the front of the tarsus obsolete Oceanites 

 b". ScuteUse of the front of the tarsus distinct . . Garrodia 



XXXVI 



