LARINJE. CETOSPARACTES. 251 



and disappear in October. They nestle in vast numbers on 

 high maritime cliffs, generally such as are frequented by auks, 

 guillemots, and other sea-birds. These breeding-places are 

 much more numerous in Scotland than in England. The 

 nests, which are generally placed on the lower parts of the 

 cliffs, are bulky, formed of grass and sea-weeds, and contain 

 two or three eggs, of a broadly oval form, two inches and a 

 twelfth in length, an inch and a half in breadth, pale yellow- 

 ish-grey, greenish-white, or light olive-green, spotted and 

 dotted all over with dark-brown and pale purplish-grey. The 

 cry of this bird is clear and rather sharp, resembling the syl- 

 lables Kittiaa, or Kittiiveea. It feeds on small fishes, which 

 it picks from the water, hovering with elevated wings, as well 

 as occasionally Crustacea and small shellfish. It walks little, 

 and not with ease, owing to the shortness of its legs ; but has 

 an easy and buoyant flight. 



Annet. Tarrock. 



Larus Rissa, and tridactylus, Linn. Syst. Nat. i. 224. 

 Larus tridactylus, Lath. Ind. Ornith. ii. 817. Larus tridac- 

 tylus, Temm. Man. d'Ornith. ii. 274. Rissa tridactyla, Kitti- 

 wake, MacGillivray, Brit. Birds, v. 



GENUS CLII. CETOSPARACTES. WHALE-BIRD. 



The " Ivory Gull" is the only known species of this ge- 

 nus, which is distinguished by the short robust bill, very- 

 short rough tarsi, and crenated interdigital membranes. 

 Body moderate ; neck of ordinary length ;' head rather 

 large, ovato-oblong, anteriorly narrowed. Bill shortish, 

 robust, compressed, straight ; upper mandible with the dor- 

 sal line somewhat concave at first, then arcuato-declinate, 

 the ridge broadly convex, the lateral sinus rather short, wide, 

 and feathered ; the nostrils medio-basal, linear-oblong, wider 

 anteriorly, covered above and behind with a sloping, thin- 

 edged plate, the edges thin, direct, the tip obtuse, very 

 slightly prolonged ; lower mandible narrower, compressed, 

 with the intercrural space rather long- and narrow, the lower 

 outline of the crura straight, forming a very slight promi- 

 nence at the commissure, the dorsal line ascending and almost 

 straight, the edges thin and somewhat inflected, the tip 

 narrow, rather obtuse ; the gape -line commencing beneath 

 the eyes. Legs very short ; tibia bare to a small extent ; 

 tarsus very short, little compressed, covered anteriorly with 



