NATURAL SCIENCES OF PHILADELPHIA. 



75 



ered, the nostrils wholly obtected by feathers. Feathers on side of lower 

 mandible retreating in a straight line obliquely upwards and backwards from 

 interramal space to rictus. Wings moderately long ; tail exceedingly short, 

 the latter contained about three and two-thirds times in the length of the for- 

 mer from carpus to end of longest primary; tail much rounded. Tarsus much 

 compressed, posteriori}' and laterally reticulate, anteriorly scutellate, much 

 shorter than the middle toe and claw. Outer and middle toes about equal in 

 length ; the claw of the latter much larger than that of the former ; tip of inner 

 claw reaching base of middle one. Claws compressed, moderatelj^ arched, 

 acute, the outer one not grooved on its outer face, the middle one greatly di- 

 lated along its inner edge. A furrow in the plumage behind the eyes. 



The genus as here constituted is restricted so as to comprehend only Iroile 

 and the species intimately related. It differs from Uria proper in several 

 l)oiuts, some of them of decided importance. For the benefit of those who may 

 be sceptical regarding the propriety of separating the two forms as genera, their 

 distinctive characters are here antithetically tabulated : 



Uria [grylle). 



Bill about equal to the tarsus ; 

 moderately compressed. 



Rictus straight, except just at tip. 



Gonys straight, half as long as cul- 

 men. 



Upper mandible not grooved. 



Tomial edges of upper mandible 

 scarcely inflected. 



Nasal fossffi wide, deep, mostly naked ; 

 nostrils partially covered with feathers. 



Feathers on side of lower mandible 

 forming a salient rounded outline. 



Tail short, slightly rounded, con- 

 tained 2f times in the wing, 



Tarsus entirely reticulate. 



Tarsus scarcely shorter than middle 

 toe without claw. 



Outer face of outer claw grooved. 



Size moderate ; no postocular furrow 

 in the plumage. 



LoMViA {troile). 



Bill much longer than the tarsus ; 

 much compressed. 



Rictus decurved for great part of its 

 length. 



Gonys concave, nearly as long as 

 culmen. 



Upper mandible grooved nearthetip. 



Tomial edges of upper mandible much 

 inflected. 



Nasal fossfe narrow, shallow, feath- 

 ered ; nostrils covered with feathers. 



Feathers on side of lower mandible 

 in a straight oblique line. 



Tail very short, much rounded, con- 

 tained 3| times in the wing. 



Tarsus anteriorly scutellate. 



Tarsus much shorter than middle toe 

 without claw. 



Outer face of outer claw not grooved. 



Size large ; a postocular furrow in 

 the plumage. 



Species — (4 ?). 



I. Depth of bill opposite nostrils not more than a third of the length of culmen. 



No white on sides of head ; bill slender, not dilated at 



base; culmen, rictus and gouys much curved 1. troile. 



A white ring and line on sides of head ; bill as in 



troile 2. rinyvia. 



No white on sides of head; bill stout, dilated at base ; 



culmen, rictus and gonys nearly straight 3. californica. 



II. Depth of bill opposite nostrils more than a third of the 



length of culmen 4. svarbag. 



LoMViA TROILE, [Linn.) Brandt. 



Lomvia Iloieri, Ray, Syn. Meth. Av., p. 120 ; fide Bryant. 

 Uria major, Ger. i, p. 549 ; fide Bryant. 

 Plautus rcftro larino, Klein. Av., p. 146, No. 2 ; fide Bryant. 

 Colymbus troille, Linn.'eus, " Fn. Suec, ed. of 1761, No. 109." Idem, Syst. Nat. 

 i, 1766, xii ed. p. 220; not Uria troille, Briinn., which is Alca lomvia, Linn., 



1868.] 



