228 Mr. H. Seebohm on the Genus Himantopus. 
writers who place such an extravagant value on structural 
characters. In my opinion H. andinus is a model represen¬ 
tative of a Semi-stilt. It has the black mantle and wings of 
the Stilts, whilst its strain of Avocet blood crops up in the 
less important characters of its recurved bill, webbed feet, 
and hind toe. H. pectoralis, on the other hand, is an ex¬ 
cellent Semi-avocet, its white mantle and the white on its 
wings proclaiming it an Avocet, whilst its straight bill and 
the absence of a hind toe show its relationship to the 
Stilts. 
The third step in the argument is the apportioning of the 
four groups to the four routes. The case is a very simple 
one. The Semi-stilt and the Semi-avocet are, by the terms 
of the hypothesis, the representatives of the two Pacific- 
coast emigrations; and as the Semi-stilt inhabits Peru, and 
the Semi-avocet Australia, there can be no dispute that the 
Semi-stilts emigrated along the American shores of the 
Pacific, and the Semi-avocets along the Asiatic shores of 
that ocean. The shores of the Pacific are so much more 
mountainous than those of the Atlantic, that the ice of the 
Glacial periods must have extended much further south on 
the former than it did on the shore of the Atlantic, a cir¬ 
cumstance which may account for the fact that the Semi¬ 
stilt and the Semi-avocet both crossed the line and settled 
in the cooler parts of the southern hemisphere. The Avocets 
consequently represent the Old-World pair, the true Avocets 
migrating along the Atlantic coast. The Stilts being the 
New-World couple, we must apportion the Atlantic coast of 
America to the true Stilts. 
Their further migrations must be considered when their 
mutual relationships have been discussed. The first group 
contains three species, which may be regarded as true 
Avocets. 
Himantopus avocetta. 
Avocetta avocetta, Briss. Orn. vi. p. 538 (1760). 
Recurvirostra avocetta, Linn. Syst. Nat. i. p. 256 (1766) ; 
et auctorum plurimorum. 
