NATURAL SCIENCES OF PHILADELPHIA. 71 



The next row of coverts are ■wholly white in their entire length, except per- 

 haps for a very brief space just at their base; and they are throughout long 

 enough to cover entirely the dark portion of the first row, reaching a little 

 beyond and overlying the commencement of the white upon the latter ; so 

 that the white is continuous and unbroken. One or two more rows of coverts 

 have precisely the same character and continue the white space uninter- 

 rupted. 



The shorter coverts, for about half inch from the edge of the antibrachium 

 are black. The last of these, however, are broadly tipped with white, which 

 white portion overlies the extreme bases of the next row, blending its color 

 with that of the latter; the anterior edge of the mirror being thus the line of 

 union of the black and white portions of these coverts, taken collectiveh'. 



In Uria coliimba, the row of great coverts is externally wholly black, or at 

 most the outermost feathers have only a ver}' narrow white tip. The amount 

 of white on the feathers increases rapidlj' from without inwards, until on the 

 innermost there is nearly or quite as much white as 'n\ grylle. In consequence 

 of the small amount of white on these coverts, the next row of coverts do not 

 overlie, nor even reach it ; there being left a broad space of dusky between 

 the white tips of the second row of coverts, and those of the first; which 

 space rapidly diminishes from the edge of the wing towards the body, forming 

 the curved crescent of dusky which is obvious upon the wing of this species. 



The mirror of Uria grylle is subject to much variation, which, however, 

 never obscures its distinctive characters in any decided degree. The greater 

 coverts may be wholly dusky ; then the mirror is the same as before, except 

 in its smaller size; the next row may be tipped with dusky, so that no white 

 comes forwaVd to coalesce with that of the greater row, and an appearance 

 like that of columba is produced ; which need not deceive, since the dusky 

 results from the second row of coverts instead of the first. All the wing 

 coverts may be tipped with dusky ; producing a variegated or spotted mirror. 

 Finally, the mirror may be only indicated by a few isolated white feathers, or 

 may be altogether wanting. 



It is to be borne in mind, that the difference in the mirror of U. grylle 

 and columba is only one of the most obvious, but not the most specific distinc- 

 tion. In the very possibly occurring cases in which there is absolutely no dif- 

 ference between si)ecimens in this respect, the absence of the white under the 

 wing, and the shape of the bill, readily distinguish columba from grylle. 



Perhaps no bird has so many synonyms as Uria grylle. Independently of its 

 reference to divers genera, a large number of nominal species have been insti- 

 tuted upon its various stages of plumage, some of them requiring brief notice. 

 A very common name for the species among pre-Linnsean writers was " Co- 

 lumba groenlandica," — obviously a mere rendering into Latin of a popular 

 designation. The word "grylle" made an early entr\' into the records, desig- 

 nating the adult plumage. Grylloides of Briinnich represents a variegated con- 

 dition ; and balthica of the same author an immature or winter state. Lac- 

 teolus of the older authors seems to have been based upon the albino condition ; 

 the bird being described as " niveus, rostro pedibu.'^que ex carneo fuscescen- 

 tibus." It is possible that Pallas, who introduced the word, may have really 

 based it upon a specimen of columla ; but this is a point of no special conse- 

 quence. Bonnaterre has another name, — '■'■nivea'" — for the same condition, 

 quoting Pallas, Sp. Z. v, p. 33. Brisson and Brehm both have a large numl)er 

 of nominal species, not necessary here to particularize. In 1817, Vieillot 

 (1. supra cit.) describes an adult under the name of Uria leucoptera^ errone- 

 ouslj' assigning it dimensions nearlj^ equal to those of Lomvia troih. At least 

 the presumption is that this Inicoptera is nothing but a large grylle, though he 

 must have been perfectly familiar with the latter. Even so late as 1824, grylle 

 is redescribed as Uria .<!capulari.s. 



The " Uria Mandlii" of Lichtenstein requires attention, having been exten- 

 sively ciuoted as a synonym of, or employed to designate, U. columba, as will 



1868. 



