The Birds’ Calendar 
after possession as they would be uninteresting 
and laborious in the acquisition. 
Even when the correct fundamental relation 
subsisting between the facts of a certain class 
is felt to be as yet undiscovered, as in botany 
and ornithology, one realizes the need of some 
provisional system, however erroneous it may 
be, until the true one shall have been found. 
As an aid to memory a system is of inestimable 
value, and in this respect a thoroughly false 
method may not be so very inferior to the cor- 
rect one. 
Birds may be grouped in three ways. That 
which claims to be the most thoroughly scien- 
tific classification is based upon anatomical 
structure, wherein the size and form of the bill, 
the number of feathers in the wing, the length 
and peculiarities of the leg (or tarsus), the num- 
ber and position of the toes, etc., are among 
the important criteria for determining the status 
of the individual. We can all certainly agree 
in saying, with Lincoln, that ‘‘ for those that 
like that kind of a thing, that would be just 
the kind of a thing they would like;’’ but if 
pressed for further unanimity, some of us would 
have to part company. 
But for the purposes of field ornithology the 
46 
