NATURAL SCIENCES OF PHILADELPHIA. 187 



The bill is black, except its sulcus. The feet are flesh colored or dull 

 whitish, becoming yellowish in the dried state. The edges of the eyelids are 

 pure white except just at the anterior canthus. 



The perfectly and uniformly fuliginous color (darkest about the face and on 

 the wings and lail) which is the ordinary plumage, sometimes gives way to a 

 much lighter, clearer and more cinereous color. Examples of this coloration, 

 doubtless due to age, are in the Philadelphia Academy and Smithsonian In- 

 stitution. The most extreme case I have met with is as follows : Neck all 

 around, upper part of back and whole under parts nebulated with ashy or 

 grayish white. Lower part of back, wing-coverts, scapulars, etc., light 

 plumbeous gray. Wings and tail ashy or plumbeous blackish, lightest on their 

 inner webs, their shafts chiefly whitish. On the face, crown aud sides of 

 the head the fuliginous holds, deepest in tint immediately around the bill. 

 The nape and hind neck, and some of the wing coverts show traces of ferru- 

 gineous. 



Chord of culmen 4 to 4-50, height of bill at base 1-50, at unguis 1-00, width 

 at base -75. From feathers on commissure to tip 3-50, from feathers on lower 

 mandible 2.50. Tarsus about 300 ; middle toe and claw 4-75, outer 4-50, inner 

 4-00. Wing 21-00, tail -10, its graduation 3-50 to 4 50. 



I have examined the type of Diomedea fusca Aud. now in the Smithsonian 

 Institution. 



The follov?ing is a synopsis of the genera and species of the Diomedeinse. 



Family PROCELLARIW.E. 



Sub-family DIOMEDEIN.'E. 



Chs. The tubular nostrils are separated, and placed on either side of the 



culmen. The hallux is absent. The exterior toes have a wide membranous 



fringe. 



Genus I. Diomedea. Bill stout, or moderately compressed. No sulcus on 

 lower mandible. Tail short or moderate, more or less rounded. Nostrils 

 large. 



A. Bill very broad. Tail short ; contained 

 nearly, quite, or more than three times in 



the wing Diomedea et Phcebastria Reich. 



1. D. EXULANS L. {spadicea Gm. Lath, (juv.) albatrus Pall. Forst., adusta Tsch. 

 Bill 7 inches. Frontal feathers forming a deep concavitj^ on the culmen ; 

 those on side of lower mandible extending to a point opposite middle of nos- 

 trils, with an exceedingly convex outline. 



2. D. BRACHYURA Tcmm. (spadicea var. B. Lath, (juv.) epomophora Less. 

 Tsch. Bp.) Bill 5 to 6 inches. Frontal feathers embracing the bill nearly in 

 a straight line : those on side of lower mandible extending hardly further than 

 on upper, with a barely convex outline. 



[2a? D. LEPTORHYNCHA Coues. Doubtfully based upon a skull differing 

 somewhat in proportions from that of brachyura. See antea.] 



3. D. NiGRiPES Aud. {brachyura juv. Cass. Lawr.) Bill 4 inches ; width at 

 base 1-25 ; height l'50j very robust for its length. Frontal outline nearly as 

 in brachyura. 



? 4. D. GiBBOSA Gould. " With a peculiar swollen and raised form of the 

 upper mandible, which moreover rises high up on the forehead. Bill 4." 

 (Probably = nigripes Aud.) 



B. Bill compressed. Tail elongated, rounded, nearly 

 half as long as the wing from the carpal joint. 

 White, with black back and wings. A transocular 



fascia (ThalassarcheV,ei(^\i.) 



1866.] 



