SPECIES, VARIETIES, AND RACES. The indi vidual is a concrete fact. A species is an induction, a generalization. (See CLASSIFICA Our idea of most species is based on a pair or only a few individuals, whereas the actual nunilwr of individuals of most species may be counted by the thousands or even mil lions. Our conception of a species varies with the number of specimens in our collections; and systematists naturally differ greatly as to the 11111ii s of many species. The best definition of spe cies is that of Lamarck: "A species is a collec of similar individuals which are perpetuated by generation in the same condition is long as their environment has not changed sufficiently to bring about variation in their habits, their character. and their forms." A variety, or subspeeies, is a group of individu als breeding true to each other, which resemble each other in color. size, etc., i. e. in characters less pronounced than those of species. Darwin calls a variety an incipient species, or a species in process of formation. Local varieties are
fixed variations of species with a wide range; they are restricted to small areas shut in by mountain ranges, etc. They are thus due to dif ferent local environments, to differences in tem perature, altitude, dryness or moisture, soil, etc. Local varieties, says Wallave. are the first steps in the transition from varieties to species. Varie ties are subdivided into 'races,' though the two terms are often used interchangeably. Huxley calls a 'a propagated variety.' Races are subdivided nto 'breeds; and these into `strains'— the numerous breeds of pigeons. as the fantail, pouter, barb, tumbler, English carrier, etc., are examples of breeds, while a strain is the least recognizable variation from some racial form. Among domestic horses, we speak of the Arabian, Clyde, or Pert-heron breed; of the Morgan or Hambletonian strains. The American trotting horse is a breed which has been formed by arti ficial selection since the year 1822.