78 GENEBAL ORNITHOLOGY. 



malm 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 cif 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 tlie highest members of the next lower group. The common 

 phrase, " below par," or "above par," is most applicable to such eases. 



Machinery of Classiflcatiou 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 eft'ect in classifying birds, ^^m■ machinery for that purpose is our inherit- 

 ance from those naturalists who held very different views from tlnise 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 ; 

 hut it is the best we have. Systematic zoology, or the practice of classification, has failed to 

 keep pace with the principles of the science ; wo are greatly in need of some new and sharper 

 " tools of thought," which shall do for zcjology what the system of symbols and formulas luive 

 done for chemistry. We want some symbolic formidatwH of our knoioledge. The invention of 

 a practicable scheme of classification and nomenclature, which should enable us to f(.>rnmlate 

 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 

 " jihylum," is a common practice ; but that, like any other pictorial representation of a " fand- 

 ly tree," is not the graphic syinbolization required. The first steps in this direction have been 

 tentatively taken already by the late Mr. A. H. Garrod and others : we already have a mother 

 of the required invention in the necessity of the case, and may hope that the fiither will not be 

 long in coming. 



Under the present sj'stem, Birds are called a "Class" of A^ertebrates, and are subdivided 

 into "orders," "families," "genera," "species" and "varieties," as already suflSciently indicated. 

 Groups intermediate to any of these may be recognized ; and if so, are usually distiuguislied 

 by the prefix suh-. Many other terms are in occasional use, as "tribe," "race," "scries," 

 "cohort," "super-family"; but those first mentioned are the best established ones among 

 EugUsh-speaking naturalists. Their sequence is fixed, as above, from higher to lower, in 

 relative rank.^ With the exceptions to be presently noted, the names of any groups are 

 arbitrary, at the wUl of the person who founds and designates them. The fi'amer 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-families, the former commonly being made to end in -irftK, the 

 latter in -inm : family Tiirdida ; sub-family Ttirdina. 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 Avords ; as, order Passeres ; but sometimes, especially in 

 cases of intermediate groups, two words are used, one qualifjdng 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 all higher groups, invariably begin with a cajiital 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 tlie name of the 



■ The expression "higher group," in the sense of relative rank in tlie taxonomic scale, will of course be dis- 

 tingui.fhell from the same expression when applied to tlic relative rank in the scale of organization of the ohjects 

 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. 



