418 TEINGA. 



conclusion : — T. acuminata was differentiated in Australia and in post-glacial times 

 despatched a colony across Behring Straits, which in process of time became T. pectoralis, 

 which is " one of the commonest of the waders " at Point Barrow (Seebohm, Trans. Norf. 

 & Norw. Nat. Soc. iv. p 307). T. pygmcsa was isolated somewhere on the outskirts of the 

 ice, possibly in the south island of Japan. T. ruficollis was isolated on the islands of the 

 Malay Archipelago, and T. suhninuta in Burma or Ceylon, a colony of the latter species 

 crossing Behring Straits after the return north and becoming T. minutilla. T. minuta was 

 doubtless isolated in India, and T. platyrhyncha in the Persian Gulf, a colony of the latter 

 species subsequently crossing Behring Straits and becoming T. bairdi. Finally, T. temmincki 

 was isolated in the valley of the Nile. 



KEY TO THE SPECIES. 



The species composing this genus are so nearly allied that it almost amounts to hair- 

 splitting to divide them even subgenerically. It is, however, convenient to divide them 

 into two groups to simplify the key to the species, and it seems possible that this sub- 

 division may have some historical significance. 



The first group consists of those species which have as much or more white than brown 

 or grey on either the upper tail-coverts or the last half-dozen secondaries (true secondaries, 

 not tertials) : — 



Wing 7 inches or more . . CrassirOStris ... 1 

 Wing 6-2 to 6-8 inch . . caimtus . . . . > 



subarquata • ■ • 



Bill 1 inch or more from fron- 

 tal feathers. More white 

 than brown on upper tail- 

 coverts. 



Bill "9 inch or less from frontal 

 bonaparti . . . . ^ feathers. More white than 



brown on upper tail-coverts. 



alpina. 

 maritima .... 



arenaria ... Hind toe absent 



Rump and upper tail-coverts 

 nearly black. 



The second group consists of those species which have very little white, either on the 

 upper tail-coverts or secondaries : — 



