464 Mr. Selby on the Birds of the Farn Islands, 



and differs in the colour of its legs, which are yellow, whereas 

 those of L. marinus, are livid or flesh-coloured. Early in Spring 

 they assemble in large flocks upon the main land opposite, and 

 are observed every afternoon to advance four or five miles into 

 the interior, alighting at intervals upon a pasture or newly-sown 

 corn-field. At this time they are very clamorous, and unite in 

 exercising these notes or calls peculiar to, and indicative of the 

 pairing season. 



Larus argentatus, Brunn. Orn. Boreal. 44. No. 149. Gmel. 



Syst. 1. 600. sp. 18. 

 Goeland a manteau bleu. Temm. Man. d'Ornith. 2. 764. 

 Herring Gull. Lath. Syn.. 6. 372. Penn. Arct. Zool. 2. 5^17, 



A few individuals of this species breed annually in company 

 with L. Juscus. They are easily distinguished by the paleness 

 of the upper parts of the body, flesh-coloured legs, and longer 

 bill. Their note is also different. In habits and manners they 

 are very similar. Both species are three years in acquiring the 

 adult plumage. 



Larus tridactylus. Linn. 1. 224. Meyer Tasschenb. Deut. 



2. 486. 

 La Mouette Cendree. Briss. Orn. 6. 175. t. 16. f. 1. 

 Tarrock Gull. Lath. Syn. 6. 392. 

 Kittiwake. Penn. Arct. Zool. 2. 529. 



This species differs from its congeners in the deficient structure 

 of its hinder toe, which is indeed no more than a knob or stump 

 unprovided with a nail. This difference however brings it in con- 

 nection with, and shews its affinity to other succeeding groups, 

 particularly Ilaladroma and Procellaria^ and it thus serves to il- 

 lustrate that doctrine of affinities and circular succession, which 

 appears to exist throughout animated nature, and which has been 

 so ably advocated, I may say demonstrated, by the pens of Mr. 

 MacLeay and Mr. Vigors. Its habits are more oceanic, if I may so 

 call them, than those of the more typical species of the Lari. It 

 never like them advances into the interior, to feed upon worms 



