acgontan Vistitapr 
81 yer Dp 
plasm also, gradually and equally influenced, a rivMd dé 25 192 
a stage when it is capable of passing on these vaxlations , 
in a stable form, until once more there are further-géer«! ¥°™ 
graphical or climatic changes. At the same time, the 
influences brought to bear on other individuals of the same 
species less far removed from their original habitat will be 
less pronounced, and we thus get the half-way individuals 
which link the two extreme forms together, until, as I have 
already said, these die out and leave the two extremes 
constantly and definitely cut off from one another. 
All birds come from ancestors comparatively few in 
number, who in turn work back to a still smaller number of 
reptile-like forms, and thence back and back to still more 
primitive forms, multicellular and unicellular protoplasms, 
etc., and no one can contend that the evolution of the proto- 
plasm has remained quiescent all this time. 
Classification of the living members of the Class “ Aves,” 
like every other classification, is intended to simplify, or 
make easy, the attainment of knowledge. In the present 
instance, the division of species should assist in the acquire- 
ment of knowledge, both of ornithology as a whole, as well 
as of each individual species, its life-history, and all other 
facts connected with it. If the classification employed helps 
towards this end, it is scientific ; if, on the other, hand, it 
renders the acquisition of knowJedge more difficult, it is not 
scientific, and should be discarded. } 
When ornithology was in its infancy, birds were lumped 
together under one name in the most extraordinary way, 
and at this period much the same degree of nomenclature 
obtained amongst civilised people as obtains to-day among 
savage tribes. Thus there were groups of birds known as 
Vultures, Hagles, Ducks, Storks, Owls, Flycatchers, and 
so on ; sometimes these were again divided into “large” or 
“small,” and sometimes a second qualifying name was added, 
denoting some conspicuous character. As time progressed, 
these larger divisions were gradually broken into smaller 
and smaller ones, until eventually most birds which differed 
conspicuously from others had a definite trivial name. To 
a2 
