Breeding-colony of Lams eburneus. 443 



of a lichen were founds which appear to have got iu acci- 

 dentally. 



The average of nine eggs was 59'9 millim. in length by 33"7 

 millim. in breadth. The gronnd-colour of five specimens is 

 almost entirely alike, viz. a light greyish-brown tint, with 

 faint admixture of yellowish green, such as often appears on 

 the eggs of L. canus, which, however, have often a deeper 

 brown or green hue. In structure and gloss all nine eggs 

 greatly resemble those of L. canus ; but the granulations 

 under the microscope are a little coarser, more uneven, and 

 in larger numbers; on the other hand the granulations are 

 perceptibly finer than in L. fuscus. The eggs are easily dis- 

 tinguished from those oiRissa tridactyla by their greater gloss, 

 and the small excrescences do not lie quite so crowded, and 

 are a little more flattened than they usually are in the last- 

 mentioned species. 



Newly hatched young in down : length of tarsus 17 millim., " 

 middle toe with claw 24 millim. White all over; the down 

 white to the root. Even in this first stage, the young in 

 down may be distinguished from the young of other species 

 by the strong and hooked claws, especially on the hind toe, 

 the somewhat marginated web on the toes, and the forward 

 nostrils. The downy covering is particularly close ; L. ebur- 

 neus in this respect is more closely related to the other species 

 of Larus than to Rissa, the hair-like tips being shorter. 

 The bill is horny brown with lighter margins ; the claws 

 light horn-colour. In a somewhat older bird the length of 

 the tarsus is 25 millim., middle toe with claw 31 millim. ; the 

 tips of the feathers appear on the shouldprs, which exhibit a 

 broad dark-brown transverse baud within the white and 

 still down-bearing tips ; the bill is horn-brown, with but 

 slightly lighter tip and edges. On account of the long claws 

 the emargination of the web appears to be larger than it 

 really is. 



