1909] The Ottawa Naturalist. 71 



called varieties of the species, which is then called a variable 

 species. "Specimen" is the word naturalists use to indicate a 

 single individual or example of a species. The reasons why one 

 species should be variable and another constant, or one very 

 local and another widely distributed, are very obscure and 

 intricate, and must be sought for amongst hereditary tendencies 

 of bygone ages. They cannot be dealt with in the present paper, 

 which treats of facts rather than causes. 



It will often be found, if we trace a "generally distributed" 

 species throughout the various districts where it occurs, that 

 some of the specimens from one locality differ slightly in certain 

 points or characters from others from a neighboring district. 

 The lower down in the scale of life we look for illustrations of 

 this the more easily we shall find them. It is less noticable in the 

 higher than in the lower forms of animal life. It is found to some 

 extent in birds, still more in insects, and in plants more than in 

 either. Some specimens will be found exactly alike from the two 

 districts, others will differ considerably. They are obviously still 

 the same species, but present what is called local variations, or 

 varieties. Follow the species up into a third district, and perhaps 

 a greater number of specimens will be found which diff'er more or 

 less from those in the first. Follow it up further, comparing 

 numbers of specimens throughout various districts right across 

 the continent. The difference between individuals in different 

 districts will probably be found to vary not nearly so much 

 according to the actual distance of the localities apart, as to the 

 difference between the geological and climatic conditions. These 

 conditions diff'er enormously, say, on the Altantic and Pacific 

 coasts. But as it is not possible to draw, so to speak, any actual 

 fine or lines of distinction between those different conditions 

 anywhere in that area, nor even to follow through any gradual 

 regularity of change from one to the other, so, in the case of our 

 widely distributed but variable species, we shall find neither any 

 sudden change of variation or form, nor any gradual regularity 

 of change. And though we may be able to find no district in 

 which the varietal forms diff'er entirely from those on all the rest 

 of the continent, those from the most climatically or geologically 

 dissimilar districts will probably be found the least Hke each 

 other, and may even be entirely different in appearance. In 

 other words, the species exists in the different localities as a 

 different "local race," the diff'erence varying probably according 

 to the diff'erence of conditions under which it has to exist. "We 

 may have every reason to assume a distinct blood relationship 

 between the various forms. Are we then to call the extremes 

 different "species"? "Would they, if brought together under 

 perfectly natural conditions, perpetuate the race, or mixture of 



