160 PROCEEDINGS OF THE ACADEMY OP 



physis slight, the tip a little decurved. The interrarnal space is narrow, and 

 densely feathered to the symphysis. The nasal tubes are exceedingly short, 

 but broad, high, and turgid, the median line only obsoletely carinated. Their 

 apex is very obliquely truncated, not at all emarginated. The orifice is large, 

 and nearly circular ; the internasal septum very thin, and not extending to the 

 termination of the nasal case. The frontal feathers extend far on the base of 

 the bill, running forward on the nasal case with a narrowly rounded termina- 

 tion, and sloping rapidly backwards and obliquely downwards. The outline 

 of the base of ihe nasal tubes is thus rendered nearly as oblique as their 

 apex. 



The wings are rather short, when folded not reaching to the end of the tail. 

 The second primary is not much shorter than the first. All the primaries are 

 rather narrow, regularly tapering to their somewhat acute tips. The tertials 

 and inner primaries are much abbreviated, making the distance in the folded 

 wing, from their tips to the end of the first primary unusually great. The tail 

 is very long, broad, and but slightly rounded, ami is contained only about 

 twice in the wing from the carpal joint. All the rectrices are broad to their 

 very tips ; which latter are squarely truncated. 



The tarsus is as long as the middle toe; moderately stout and compressed ; 

 covered with small somewhat elongated irregularly shaped plates, which are 

 rough and elevated, especially posteriorly, and are not notably different in size 

 or shape on the two aspects of the tarsus. Thetibire are feathered to very near 

 the joint. The inner lateral toe with its claw barely reaches the base of the 

 middle claw. The outer lateral toe is longer than the middle; its claw how- 

 ever so short, as hardly to rf ach to the tip of the middle claw. Claws are 

 rather large, little curved, moderately compressed and acute ; the inner edge 

 of the middle one dilated. The hallux is unusually developed, and somewhat 

 depressed in situation ; long, stout, acute, and a little curved. 



The size is moderate; the form compact and robust; the color entirely pure 

 white. 



This is one of the most remarkable generic types of the Proccllariinx. It is 

 doubtless most nearly related to Daptioh, with which genus its " build " cor- 

 responds closely. But, as will be seen on comparing the diagnosis given, it 

 differs in many details of structure, particularly those relating to the bill. From 

 ^Estrelata the pecularities of bill, of the hallux, comparative lengths of wings 

 and tail, etc., readily distinguish it. The genus has a " physiognomy" or 

 " facial aspect " that is peculiarly its own. The long depressed sloping fore- 

 head is found in no other Procellaridian. This is produced mainly by the flat- 

 tening and elongation of the bones composing the forehead ; but aided to a 

 considerable degree by the great forward extension of the frontal feathers, 

 which gives to the bill and nasal tubes their extreme brevity ; causes such a 

 long rictus ; and places the eye, apparently, at so great a distance from the 

 corneous base of the bill. 



Pagodroma nivea (Gm.) Bon. 



Procellaria nivea, Gm., S. N. 1788, i. part ii. p. 562, and of authors generally. 



D i pi ion niveum, Stephens, Shaw's Gen. Zool. xiii. p. 243. 



Thalassoica nivea, Reichcnbach, tab. 22, fig. 791, 792. 



I'ugodroma nivea, Bonap trte, C. A. 1855, ii. p. 192. 



Procellaria Candida, Peale, Zool. U. S. Expl. Esped. 1848, p. 295. 



Pagodroma, var. major, Bonaparte, 1. c. 



Pagodroma, var. minor, Bonaparte, 1. c. 



Procellaria nivea minor, Schiegel, .Won. Proc. Mus. Pays-Ba3, 1863, p. 16. 



Habitat. Antarctic Ocean and Continent. 



Independently of differences in absolute size of body, the species presents 

 unending variations in size, and, to some degree, in shape, of the bill. Speci- 

 mens differ in this respect by as much as a fourth of the whole length of the 



[May, 



