2370 The Zoologist — November, 1870. 



rapidly deflected; rictus straight, except just at tip ; gonys ascending, 

 straight, short, about half as long as the culmen. No groove in sides 

 of upper mandible near its tip; commissural edge of upper mandible 

 scarcely inflected. Nasal fossa wide, long, deeply excavated, 

 partially bare of feathers, which do not wholly obtect the nostrils. 

 Feathers extending on sides of lower mandible with a salient rounded 

 outline. Wings and tail very short, the latter contained about two or 

 two-thirds times in the length of the former from the carpal joint to 

 the end of longest primary; tail slightly rounded. Tarsus much 

 compressed, entirely covered with polygonal reticulations, somewhat 

 scutelliform on the inner aspect; slightly shorter than the middle toe 

 without its claw. Outer and middle toes equal in length ; the claw 

 of the former much smaller than that of the latter, tip of inner claw 

 just reaching base of middle one. Claws compressed, moderately 

 arched and acute ; the outer one grooved along its outer aspect, the 

 middle one greatly dilated along its inner edge. No postocular furrow 

 in the plumage. 



In the preceding diagnosis the characters of the genus are so drawn 

 as to exclude the large species of Lomvia. Few writers have made 

 this generic distinction, for which, notwithstanding, there is abundant 

 reason, as may be seen upon a critical comparison of the two types of 

 form, and as will be satisfactorily demonstrated at length under head 

 of Lomvia. It need only be noted here, that the structure of the 

 bill and feet are in many respects very diff'erent in the two genera. 



The genus as here framed comprehends three distinct species, 

 intimately allied to each other. 



Disregarding other and less prominent though very valid distinc- 

 tions, the three species of Uria may be at once recognized by the 

 following characteristics: — 



A large while space on wing, entire. No white about head. - \ Gryllc. 



A large while space on wing, partially ilivided by a black line. No 



white about head. - - - - - - 2. Columla. 



No white on wing. Feathers around and behind eye and at base of 



bill, white. - - - - - . - 3. Carlo. 



Or they may be still more briefly and quite as satisfactorily 

 characterized thus : — Caibo, upper and under surfaces of wings black ; 

 Grylle, upper and under surfaces of wings white; Columba, upper 

 surface of wings white, under black. 



The division of the white mirror on the upper surface of the wings 

 of Columba is not the most important point of coloration, though the 



