﻿43° SMITHSONIAN -MISCELLANEOUS COLLECTIONS [VOL. 4/ 



have come together from the most different mountain systems 

 bordering the Irkutsk Amphitheater and Lake Baikal, and that the 

 dippers nesting in each of these mountains, such as the Sayan, the 

 Primorski Khrebet, and the Vitim plateau, not to speak of others 

 more remote, differ more or less appreciably from each other. 



All these questions are of the utmost importance and interest, but 

 with the present utterly inadequate material at the disposition of the 

 ornithologists, it is scarcely possible to more than lift a corner of the 

 veil. Until the true inter-relations of these birds have been ascer- 

 tained ; until the distribution of the forms thus established has been 

 actually mapped in considerable detail ; and until the results thus 

 gained have been verified by correlation with the physiographic fea- 

 tures of the country in the field by competent observers ; until then 

 we shall have nothing but guesses. 



The story of the dippers is not an isolated instance. It is, on the 

 contrary, a typical example of the status of a vast majority of the 

 holarctic animals whose geographical distribution is of the utmost 

 importance for a correct understanding of all the phenomena in- 

 volved. It will require a wisely planned and carefully conducted 

 biological survey with ample means at its command and a central 

 depository for the vast material which must be gathered by specially 

 trained field agents before the many problems I have only hinted at 

 can be rationally approached. The necessity of attacking the propo- 

 sition in some such way may be further inferred from another ex- 

 ample furnished by the dippers. I need only mention that no less 

 than nine different forms of palearctic dippers have been described 

 during the last two years, the scant material upon which these are 

 mostly founded beino- distributed amon°- six different museums. 



