184 PROCEEDINGS OF THE ACADEMY OP 



much less compressed ; deeper at the middle, notwithstanding that the con- 

 cavity of the culmen is much greater; and with other well-marked peculiar- 

 ities, as follows : — 



The dorsal outline is exceedingly concave, dipping down rapidly from the 

 foFfhead, and then again being much elevated on the ungual portion. The 

 culininicorn is broad, flvttened, depressed, with no trace of carination. Its 

 colored base, instead of being acutely pointed, (as in chlororhr/ncha.) con- 

 tinues of a uniform width past the nostrils to the feathers, where it is broadly 

 rounded with a geotle convexity, Taere exists posterior to the nostrils a 

 naked space of sofc skin ; but this is trapezoidal, not triangular in shape, in 

 consequence of the different shape of the base of the culminicorn, just 

 described. 



The lateral sulcus is nearly straight to the unguis, where it is greatly 

 deflected. It runs high up along the bill ; or ra'her the dorsal outline of the 

 culmen dips, towards the middle of the bill, so fir down, that it almost lies 

 on a level with this sulcus. The culminicorn is thus allowed scarcely any- 

 thing of a lateral aspect in the middle portion of its extent. The latericorn, 

 as a consequence, is very deep throughout, and its commissural outline is 

 decidedly less curved. The two ungues are stout, deep and short ; with con- 

 siderable more convexity of outline, and less elongation and decurvation of 

 their apices than is seen in chlororhyncha. 



The dorsal outline of the inferior mandibular rami is quite straight. The 

 interramicorn is prominent, but not so long as in chlororhyncha. 



The outline of the feathers is almost exactly as in melanophrys ; i. e., they 

 lie over the base of the culmen iu nearly a straight line, or with a slight con- 

 cavity ; and thence extend nearly straight down the sides of the bill. There 

 is no trace of the reentrant angles at the sides of the base of the culminicorn 

 seen in chlororhyncha. The feathers on the lower mandible have the same out- 

 line as those of melanophrys or chlororhyncha. 



The colors of the bill are quite different from those of any other species, 

 though coming nearest to cJdororhyncha. The culminicorn is clear light yel- 

 low ; (not bright orange ;) and the edges of the inferior mandibular rami for 

 Ihreefourihs their extent are also yellow. There is no yellow line along the 

 sides of the base of the lower mandible at its junction with the feathers. The 

 rest of the bill is black. " In its youthful state the head and neck are dark 

 gray, and the bill is of an almost uniform brownish black, with only an indica- 

 tion of the lighter color of the culmen." (Gould.) 



The plumage is quite the same as that of chlororhyncha. The color of the 

 back is darkest posieriorly, being anteriorly more plumbeous, and shading 

 into the grayish pearl which washes the neck and head of the majority of 

 specimens. Usually the feathers about the ej-es are more or less dark-colored. 



In young birds the whole head and neck is clouded with plumbeous gray ; 

 and the transocular fascia is more conspicuous. 



Bill (chord of culmen) 4-50; height at base 1-75 ; at middle MO, at unguis 

 1-25 ; width at base 1-20. Tarsus 3-25 ; middle toe 5-00, outer toe 4'75, inner 

 toe 4-25. Wing 21-00. Tail 8 to 9. 



I have before me Audubon's type of the '^ cklororhyncho.s" of his works. It 

 is an example of cidminata Gould; and was doubtless procured elsewhere 

 than " not far from the Columbia River," as fals'-ly stated. This specimen 

 (No. 272G of the Smithsonian Register) is also described by Mr. Lawrence, 

 1. c, under the same name. 



1 have a distinct impression of having seen, in some old work, a plate of 

 this species (as evidenced by the yellow along the ramus of the under man- 

 dible inUeid of at it-' feathered base) under the name of ^^ chlororhynchos ;" 

 but 1 cannot now call to mind the reference. 



DiOMEDEA CHLORORHYNCHA Gmelin. 



Diomedea chlororhyncha, Gm. i. 1788, p. 568. Lath. Syn. v. p. 309, pi. 94. 



[May, 



