78 
GENERAL ORNITHOLOGY. 
malia and Aves collectively, that every mammal must be more highly organized than every 
bird. It is difficult to say how a mole or a mouse is a more elaborate or more capable creature 
than a canary-bird, physically or mentally. The relative rank of two groups is determined 
by balancing the aggregate of their structural characters. In large series, the average of 
development, not the extremes either way, is taken into account ; so that the lowest members 
of a higher group may be below the highest members of the next lower group. The common 
phrase, below par," or above par," is most applicable to such cases. 
Machinery of Classification. — The inexperienced student may be glad to be given some 
explanation of the way in which the taxonomic principles we have discussed are applied, and 
carried into practical effect in classifying birds. Our machinery for that purpose is our inherit- 
ance from those naturalists who held very different views from those which touch the evolu- 
tionary key-note of modern classification. It is clumsy, and does not work well as a means of 
expressing the relations we now believe to be sustained by all organisms toward one another ; 
but it is the best we have. Systematic zoology, or the practice of classification, has failed to 
keep pace with the principles of the science j we are greatly in need of some new and sharper 
tools of thought," which shall do for zoology what the system of symbols and formulae liave 
done for chemistry. We ivant some symholic formulation of our knowledge. The invention of 
a practicable scheme of classification and nomenclature, which should enable us to formulate 
what we mean by Turdus migratorius, as a chemist symbolizes by SO4H2 what he understands 
hydrated sulphuric acid to be, would be an inestimable boon to working naturalists. The 
mapping out of groups with connecting lines to indicate their genetic relations, in the form, of a 
" phylum," is a common practice } but that, like any other pictorial representation of a fami- 
ly tree," is not the graphic symbolization required. The first steps in this direction have been 
tentatively taken already by the late Mr. A. H. GaiTod and others : we already have a mother 
of the required invention in the necessity of the case, and may hope that the father will not be 
long in coming. 
Under the present system. Birds are called a ''Class" of Vertebrates, and are subdivided 
into ''orders," "families," "genera," "species" and "varieties," as already sufficiently indicated. 
Groups intermediate to any of these may be recognized ; and if so, are usually distinguished 
by the prefix sub-. Many other terms are in occasional use, as "tribe," "race," "series," 
"cohort/' "super-family"; but those first mentioned are the best established ones among 
English-speaking naturalists. Their sequence is fixed, as above, from higher to lower, in 
relative rank.^ With the exceptions to be presently noted, the nam.es of any groups are 
arbitrary, at the will of the person who founds and designates them. The framer of a genus, 
or the describer of a species, calls it what he pleases, and the name he gives holds, subject to 
certain statutory regulations which naturalists generally agree to abide by. The exceptions 
are the names of families and sub-tamilies, the former commonly being made to end in -idee, the 
latter in -incs : family Turdidce ; sub-family Turdince. This is a great convenience, since we 
always know the rank intended to be noted by these forms. The names of groups higher than 
species are almost invariably single words ; as, order Passeres ; but sometimes, especially in 
cases of intermediate groups, two words are used, one qualifying the other ; as, sub-order 
Passeres Acromyodi, or oscine Passeres. A generic or sub-generic name is always a single 
word ; these, and the names of aU higher groups, invariably begin with a capital letter. 
Until quite recently, the scientific name of any individual bird almost invariably consisted 
of two terms, generic and specific, — the name of the genus, followed by the name of the 
1 The expression "higher group," in the sense of relative rank in the taxonomic scale, will of course be dis- 
tinguished from the same expression when applied to the relative rank in the scale of organization of tlie objects 
classified. An order of birds is a " higher group " than a family of birds, in the former sense, but no higher than 
an order of worms, in the latter sense. 
