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 higliest 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 whicli the taxonomic principles we have discussed are applied, and 

 carried into practical effect in classifying birds. Our machinery for that pui-pose is our inherit- 

 ance from those naturalists who held very different views from those which touch the evolu- 

 tionary key-note of modem classification. It is clumsy, and does not work weU as a means of 

 expressing the relations we now believe to be sustained by aU organisms toward one another ; 

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

 keep pace with the principles of the science ; 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 have 

 done for chemistry. We want some symbolic 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. Garrod and others : we akeady 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 sufliciently 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 

 Enghsh-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 will 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 -id<£, the 

 latter in -ince : famOy Turdidce ; sub-famUy Turdime. This is a gi'eat 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 all 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 the 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. 



