propose;d explorations and investigations 259 



sentative collection consisting of single specimens of typical forms 

 occurring across the vast continent from England to Kamchatka, 

 and no museum in the world — nay, not even all the museums put 

 together — could furnish such series of any large group of animals 

 as are required by modern methods. 



(/) Miscellaneous allied questions. — It would carry us too far 

 were we to go into detail, pointing out all the important problems 

 which wait for a solution through a study of the life of Siberia and 

 an intelligent comparison with the corresponding area of our own 

 continent. The evolution of the steppe and tundra animals and their 

 spreading at periods when the steppe or the tundra life zones tem- 

 porarily at least extended into other regions ; the significance of the 

 marine life, the seals, crustaceans, sponges, etc., in Lake Baikal ; the 

 question as to the efficiency of the marine transgression of the Arctic 

 Ocean east of the Urals in establishing an effective barrier against 

 Siberian fauna and flora expanding into Europe during glacial times, 

 either alone or in conjunction with glaciation ; the climate of the 

 interior of Siberia during the same period and the curious mixed 

 fauna, as shown by the fossils from the New Siberian islands and 

 the mouth of the Yana riv^er ; the very origin of the fauna which 

 apparently radiated from some point in that vast territory reaching 

 as far west as the British islands and as far east as Greenland — these 

 and many other problems are closely connected and are all waiting 

 for further elucidation based upon the bringing together under one 

 comprehensive system of detailed material for minute study and 

 exact correlation. 



9. Some probable systematic residts. — One of the aspects of the 

 proposed exploration which must not be overlooked is the great 

 increase in the systematic knowledge of the fauna and flora of north- 

 ern Asia and Europe that must result from definitely planned and 

 executed field work. While it is impossible to form any accurate 

 estimate of the probable results in this direction, a general idea of 

 the outcome may easily be obtained. 



Before the beginning of the work of the Biological Survey of the 

 Department of Agriculture, the known mammal fauna of North Amer- 

 ica consisted of about 350 species. As a result of the work carried 

 on by this Survey, the number of recognized forms is now between 

 1,600 and 1,700. In that portion of the Old World which we propose 

 to explore there are now known about 600 mammals. An incresase at 

 least as proportionately great as in America is to be expected; in 

 other words, we may look for the discovery of nearly 2,000 mammals 



