ORNITHOLOGICAL EXPLORATIONS. 343 



thalos caudatus, and Lagopus muta, which we suspect to be really dis- 

 tinguishable, not having had the opportunity of a personal inspection of 

 specimens. 



All the peculiar forms attributed to Kamtschatka, according to Table 

 XIII, are very closely related to Palsearctic forms, with the exception 

 otHaliwetus hypoleucus, the status of which is somewhat doubtful, so as 

 to justify us in excluding it from the present discussion. But these 

 forms belong to a class quite different from those mentioned above, being, 

 as they are, of consi.lerable variability, so as to possess representative 

 conspecies or subspecies in the different provinces of the Pal^arctic 

 region.* 



We have therefore simply found what we, a priori, might have ex- 

 pected, viz, that those variable forms which in other countries have 

 been modified, more or less, would show corresponding modifications 

 when occurring in a country of so peculiar a character and so great iso- 

 lation as the Kamtschatka Peninsula. 



The character and amount of this modification is remarkable in sev- 

 eral respects. In every instance it consists in an increase of the white 

 color as compared with the nearest allied forms. In fact, all the pecu- 

 liarly Kamrschatkan birds possess a greater amount of u-hite than any of 

 their allies, wherever these may reside. So extreme is this tendency to- 

 wards whiteness that one species, Astur candidissimus, has become 

 entirely white, while another, Parus hamtschathensis, is nearly so. 



The example of the Kamtschatkan ornis shows conclusively that the 

 theory of climatic conditions producing the geographical subspecies, 

 races, or whatever they may be styled, does not hold good, at least as 

 for as the increase of the white color at the cost of the others, espe- 

 cially of black, is concerned. It was already recognized long ago, as far 

 back as Gloger's earliest days, that the Siberian ornis generally showed 

 a tendency toward an increase of the white color. A similar tendency 

 seemed to obtain in forms living nearer the Arctic, and consequently 

 it was concluded that the white color was due to the increased cold. 

 Finding now that the peculiar Kamtschatkan forms are considerably 

 whiter than in any other part of Siberia, the natural inference would be 

 that Kamtschatka had a climate much severer than any other place. 

 Since we know that such is not the case, however, the logical conclu- 

 sion is that the theory of the cold being the direct cause of the increase 



*It is interesting to remark in this connection, that all the peculiar forms (with the 

 above exception) have nearly allied representatives in Northwestern Europe. 



