55S LARUS GLAUCUS. 



all white at the end; the head and neck white, streaked tcith 

 very pale hrown ; All the other parts pure white. In summer, 

 the bill gamhoge-ijelloic, the j)atch on the loicer mandible car- 

 mine, as are the edges of the eyelids ; the head and neck pure 

 lohite, the other parts as in wi?iter. Young with the bill 

 brownish-black toicard the end, at the base greyish-yellow, the 

 feet flesh-coloured ; the general ground colour of the plumage 

 pale yell Old sh-grey ; the head and neck longitudinally streaked 

 xoith very pcde broion ; the upper parts with transverse irregu- 

 lar bands ; thelower confusedly mottled and barred with jiale 

 broion and yellowish- white; the quills greyish-white, irregu- 

 larly marked loith pale-brown ; the tail pale-grey spotted and 

 barred with pale-brown. 



Male in Winter. — This species, which is about the 

 same size as the Black -backed Gull and equally robust, has 

 the body large and full ; the neck of moderate length and 

 thick ; the head large, ovate, anteriorly narrowed. 



The bill is shorter than the head, stout, less compressed 

 than usual, slightly higher tOAvard the end than at the base ; 

 the upper mandible with the dorsal line nearly straight for 

 half its length, arcuato-declinate toward the end, the ridge 

 broadly convex, the sides rapidly sloping and slightly con- 

 vex, the nasal groove very narroAV, the edges sharp, direct, 

 toward the end arcuato-declinate, the tip obtuse ; the lower 

 mandible with the angle long and narrow, the outline of the 

 crura nearly straight until near their junction, when a mode- 

 rate prominence is formed, the dorsal line ascending and 

 very slightly concave, the sides nearly erect and flat, the 

 edges sharp and slightly inflected, toward the end decurved, 

 the tip narrow but obtuse. 



The nostrils are linear-oblong, wider anteriorly, five- 

 twelfths of an inch long, medial, nearer the margin. The 

 eyes are rather small, their aperture five-twelfths. The feet 

 are of moderate length and rather slender ; the tibia bare for 

 three-fourths of an inch ; the tarsus slender, compressed, 

 with twenty-six anterior scutella ; the hind toe elevated, 

 very small, with two scutella ; the anterior toes of moderate 

 length, slender ; the second considerably shorter than the 



