Beebe's Monograph of the Pheasants A Monograph of the Pheasants William Beebe

adopted as the subspecific riterion, what a lot of changes we would be in for. Think of the opportunities among the Empidonaces, and the gulls ! Oberholser (loco citato, p. 79) implies that because a form is clearly a "geographic race," this consideration alone is a reason for employment of he trinomial. Is it necessary for him to be reminded that according to widely held current belief the great majority, if not all, of the lesser differ: entiated species, among the higher vertebrate animals, are but the results of geographic variation and isolation? There may be species of hybrid origin, but if so, they are relatively rare. Geography, the evolution of habitats through time, has been the sine qua non of vertebrate speciation: Very many good species are "merely" geographic variants. The subspecies concept will fall, just as some few people devoutly hope it will (and we will get back to pure binomials for every form recognizable at all), if it fails to be used on a consistently definite basis. Of course there is no real phylogenetic difference between a species and a subspecies. Degree of difference is a subjective matter; and the only criterion left is that of intergradation, actually known to exist.--J. GRINNELL, Museum of Vertebrate Zoology, Berkeley, California.