218 THE DUSKY SHEARWATER. 



margins, the outer toe slightly longer than the third. Claws small, slightly- 

 arched, compressed, obtuse. 



Plumage soft, full; the feathers rounded, those of the back and wings 

 rather compact. Wings long; primaries tapering, rounded, the first longest, 

 the rest rapidly graduated; secondaries of moderate length, rounded. Tail 

 rather short, much rounded, of twelve feathers. 



Bill light blue, the tips black, mouth light blue. Edges of eyelids light 

 blue, iris bluish-black. Outside of tarsus and toes indigo-black, inside and 

 webs pale yellowish-flesh-colour; claws bluish-black. The upper parts are 

 sooty-black, the lower pure white. 



Length to end of tail 11 inches, to end of wings 10^, to end of claws Hi; 

 extent of wings 26^; bill along the back 1^, along the edge of lower man- 

 dible If; tarsus 1^; outer toe 2, its claw ff. 



Genus V.— THALASSIDROMA, Vigors. PETREL. 



Bill shorter than the head, slender, as high as broad at the base, extremely 

 compressed at the end; upper mandible with the nostrils dorsal forming a 

 tube on its ridge at the base, on which the dorsal line is concave and ascend- 

 ing, then abrupt, afterwards, for a short space, straight, and lastly decurved, 

 the sides separated by a groove, convex, the edges sharp and inflected, the 

 tip decurved, slender, acute; lower mandible with the angle rather long, 

 narrow, and pointed, the dorsal line beyond it decurved, the sides erect, the 

 edges sharp, the tip decurved, acute. Head of moderate size, rounded 

 above; neck short; body rather slender. Feet rather long, slender; tibia 

 bare at its lower part; tarsus slender, reticulate; hind toe minute, with a 

 conical deflected claw; anterior toes of moderate length, slender, scutellate, 

 webbed, the third and fourth about equal. Claws slender, arched, com- 

 pressed, acute. Plumage very soft and blended, the feathers distinct only 

 on the wings, which are very long, with the primaries a little incurved 

 toward the end, the second longest, the first and fourth about equal; tail 



