NATURAL SCIENCES OF PHILADELPHIA. 183 



which his extensive researches ia almost every departmeat of Zoology so 

 justly entitle him. 



DiOMEDEA CAUTA Gould. 



Diomedea cauta, Gould, P. Z. S. viii. p. 177. Id. Ann. Mag. Nat. Hist. xiii. 

 1844, p. 360. Id. B. Aust. pi. 40. Gray, Gen. Birds, (plate of bill), 

 and of authors. 



Habitat. — From the south coast of Van Di(-men's Land. 



A beautiful species having the colors of plumage of the mdanophri/a group ; 

 readily di.<tinguishable from all other species by the following peculiarities in 

 the shape and color of the bill, and outline of the frontal feathers. 



The frontal feathers lie in a straight or slightly convex outline across the 

 base of the culmen, and then descend perpi-ndicularly to the commissure ; 

 forming a slight reesntrant angle on each side of the base of the culminicorii. 

 From exactly opposite their termination on the cominissu-al edge of the up[)er 

 mandible those on the lower start, and dsscend in a straight line with a 

 slight forward obliquity, forming a very obtuse angle with those on the upper 

 mandible. 



The dorsal outline of the culmen descends from the forehead with a gentle 

 curve, to rise again on the unguis, but not so high as at the forehead. The 

 point of greatest concavity is opposite the middle of the bill. Basally the 

 culminicorn agrees with that of culminata and chlororhyncha, and differs from 

 melanophrys, in not widening behind the notrils, nor descending to overlap 

 their bases and meet the upper edge of ttie latericorn ; a narrow sub- 

 rectangular space thus left being covered only wiih soft skin. 



The latericorn is very broad throughout as corapured with the culminicorn ; 

 i. e., the lateral sulcus is placed high up. The latericorn is exceedinaly deep 

 at its base, running high up towards the sides of the baoe of the culmiuicorn, 

 and, in consequence of the strong upward iuflectiou of the commissure 

 towards its base, the sides of the under mandible are also very deep basall}', 

 and run high up to form an acute angle with the feathers at the commissure. 



The nosirds present no discrepancies from other spncies of this group. 



" Bill light vinous gray or bluish horn color, except on the culiuen where 

 it is more yellow, particularly at the base; the upper mandible is surrounded 

 at the base by a narrow belt of black, which also extends on each side of the 

 culmen to the nostrils ; base of lower mandible surrounded by a belt of rich 

 orange, which extends to the corners of the mouth." (G>)uld.) 



Chord of culmen 4-75; height at b-ise 1-90; width 1-25; height at unguis 

 1"'25; from feathers on lower mandible to the tip of its unguis 3-75. Tarsus 

 3-25 ; middle toe 5-00 ; outer toe 4-75 ; inner 4-25 ; wing 2200 ; tail 10-00. 



The plumage is th it of melanophrys even to the transocular dark fascia ; but 

 this in the sjiscimen before me extends quite to the bill, which is nut the case 

 ia the numerous specimens of melanophri/s examined. 



A suffusion of the head and neck with pearly gray is doubtless indie itive 

 of immaturity, as is the case with other species. 



This bird is superbly figured in Mr. Gould's and Mr. Gray's plates cited 

 above. The latter is an exceedingly accurate delineation of the bill. 



Diomedea culminata Gould. 



Diomedea chlororhynchos, of Audubon's Works; witness the type specimen it- 

 self. Lawrence, Gen. Rep. Birds, N. A., 1858, p. 822. (Excl. syn.) 

 Diomedea culminata., Gould, Ann. & Mag. N. H. 1844, xiii. p. 3fil. Id. B. Aust. 

 vii. pi. 41. Gray, Gen. Bds., 1849, pi. 179. 

 This species in color of plumage is quite identical with chloroi-hi/ncha, and 

 the bill, in its general characteristics of shape, most resembles that of the 

 latter species. But the bird is much larger, stouter and heavier, as will be 

 seen by comparing the dimensions given. The bill in general terms may be 

 stated to be heavier and stronger, though not longer than that chlororhyncha ; 



1866.1 



