274 
Mr. G. E. H. Barrett-PIamilton on 
whieli in allied forms are already white have this colour 
u still purer and more dazzling in the Kamtschatkan forms/ 5 
while “ the other colours seem to be purer, and, in many 
instances, at least, to be more intense also/ 5 The colour 
which seems to suffer the most reduction is black, but that 
is only as regards intensity. 
Arguing from the facts that the peculiar Kamchatkan 
forms are considerably whiter than those of any other part 
of Siberia, that the climate of Kamchatka is less severe 
than that of Siberia generally, and that the white forms are 
not Arctic, being found so far south as 53° north latitude, 
Dr. Stejneger believes that the “ theory of climatic conditions 
producing the geographical subspecies, races, or whatever 
they may be styled, does not hold good, at least as far as the 
increase of the white colour at the cost of the others, 
especially of black, is concerned. 55 
The facts, as observed in connection with the peculiar 
Kamchatkan birds, do not, he thinks, bear out the 
conclusions deduced from observations made “ long ago, as 
far back as Gloger 5 s earliest days/ 5 that since “the Siberian 
ornis generally showed a tendency towards an increase of the 
white colour, 55 and “ a similar tendency seemed to obtain in 
forms living nearer the Arctic/ 5 consequently “ the white 
colour was due to the increased cold. 55 
There are so many, as it seems, clear instances of the 
parallel tendency of the mammals and birds of a whole 
region or district to vary in a particular direction, either 
under the influence of Natural Selection or of the direct 
stimulus of the weather and environment, but, in any case, 
to suit the particular climatic conditions to which they are 
exposed, that T should be loth to think that Dr. Stejneger 
is right here, and 1 feel bound to search for some other 
explanation of so striking a case of parallel variation—some 
explanation which shall be compatible with the idea of 
climatic influence. It is important to remember that such 
phenomena as those which Dr. Stejneger describes can only 
be said to owe their existence to the influence of climate in 
so far as such influence does not conflict with or run counter 
