July 15, 1897] 



NATURE 



257 



further because it confuses matters to use it in a new sense to 

 the exclusion of the word commonly used in that sense. More- 

 over, it is a pity, where it can be avoided, to use the word so 

 that it has different weights in different cases." 



After calling attention to the great confusion and difficulty 

 caused by the multiplication of species in genera which, in any 

 case, contain a large number of specific forms, Mr. Roosevelt 

 proceeds to make some very important remarks concerning genera 

 which contain only one or two forms. He observes that — " The 

 points of resemblance between beasts like the wolverines, the 

 beavers, and the moose of the two northern continents are far 

 more important than the points of difference. In each of these 

 cases it does not much matter whether these animals are given 

 separate specific rank, because in each case the Old World and 

 the New World representatives make up the whole genus ; but 

 even here it would seem to be a mistake to separate them speci- 

 fically unless they are distinguished by characters of more than 

 trivial weight. The wapiti and Scotch red deer, for instance, 

 are markedly different, and the differences are so great that they 

 should be expressed by the use of specific terms. If the Amer- 

 ican moose and the Scandinavian elk are distinguished by specific 

 terms of the same value, then it ought to mean that there is 

 something like the same difference between them that there is 

 between the red deer and the wapiti ; and, as far as our pre- 

 sent knowledge goes, this is not so. The wolverines, beavers, 

 and moose of the two continents should only be separated by 

 specific terms if the differences between each couple are of some 

 weight, if tiiey approximate to the differences which divide the 

 red deer and the wapiti, for instance ; and I know that even 

 these two may intergrade." 



With these sentiments we most cordially agree. Although we 

 may prefer to regard each of the couples referred to as con- 

 stituting only a single species, the harm done by dividing them is 

 comparatively slight, not only, as Mr. Roosevelt states, because 

 they are the sole representatives of their respective genera, but 

 also from the fact that the members of each'pair have the same 

 ?^nglish title ; thus at once indicating their relationship and dis- 

 tribution. 



If it be admitted that it is advisable to distinguish closely 

 related forms from those more widely separated by means of 

 nomenclature, the next question is whether it is preferable to do 

 this by means of subgenera or subspecies. To illustrate this 

 the case of the deer may be cited. By many writers of the 

 ]iresent day the genus Cerviis is taken to include all the deer 

 furnished with brow-antlers, of which the wapiti is the only Amer- 

 ican representative. In this sense the genus may be split up into 

 several subgenera, such as the Red Deer and Wapiti group 

 {Ce>i'iis), the Japanese Deer group (Psetidaxis), the Fallow Deer 

 group (Damn), the Sambar group {A'usa), and the Swamp 

 Deer group (Riiceiius) If we admit numerous species, we have 

 in the fir^t group the Red Deer (Cerfus elaphiis), the Barbary 

 Deer (C. barbariis), the Maral (C. niarai), the Wapiti (C. 

 canadensis), the Asiatic Wapiti (C enstephanus), &c. In the 

 fourth we have the Sambar (C unicolor), the Equine Deer (C. 

 equinus), the Rusa (C htppe/aphus),i\\e: HogDeer (C. porctnus), 

 &c. Now, in the first group the Red Deer and the Maral are 

 very closely allied, as are the true and the Asiatic Wapiti, and 

 to retain these as species, and at the same time to express their 

 true relationships, it is necessary to restrict the term Cervtts to the 

 Red Deer group, and to take the subgenus Strongyloceros for 

 the Wapitis. This entails the raising of Psetidaxis, Dama, 

 Pttsa, &c., to the rank of genera. Similarly the Sambar, 

 Kquine, and Rusa Deer must form one subgenus of A'lisa, and 

 the Hog Deer a second. But this scheme has the disadvantage 

 of splitting up the brow-antlered, or typical deer {Cervus) into 

 several genera, which are much more closely related than is 

 Cervus in its wider sense to the other usually accepted genera of 

 the family, such as Alces, Rangifer, Capreolus, &c. We are, 

 therefore, very little forwarder by this arrangement, by which we 

 also lose sight of the fact that the brow-antlered deer (Cervus)' 

 are distributed o\er the greater part of the two northern con- 

 tinents, as well as India and the Malayan countries. On the 

 other hand, if we adopt subspecies, the Maral becomes a sub- 

 species of the Red Deer, as C. elaphus viaral, and the Asiatic 

 Wapiti of the true Wapiti as C. canadensis eustephauus, while 

 the Equine and Rusa Deer respectively rank as subspecies of 

 Sambar under the names of C. unicolor eqnintis and C. unicolor 

 hippelaphus. Similarly, the Siberian ranks as a subspecies of the 

 Indian tiger ; while the brown and grizzly bears of Kamschatka 

 and North America are ranked as subspecies of the European 



NO. 1446. VOL. 56] 



brown bear {Ursus arclus). Otherwise, the lion must be 

 separated subgenerically from the tiger, and the brown and 

 grizzly bears from the black bears. Which is the simpler, and, 

 to most minds, the most philosophic arrangement, needs no 

 mention ! 



Of course there are difficulties in such an arrangement, as 

 there are in all sublunary matters ; and in many cases there must 

 and will be great difficulties in deciding as to what amount of 

 difference constitutes a species and what a subspecies. But the 

 same difficulty occurs when the term species is used in a more 

 restricted sense. And it may be mentioned that even when so 

 employed, subspecies are recognised by American writers. If it 

 be necessary to indicate such " sub-subspecies," quadrinomials 

 must apparently be employed, but these need only be mentioned 

 for the benefit of the advanced specialist. The unfortunate thing 

 in the matter is the existence of the " personal equation," which 

 is one very difficult to get over. If, however, it be borne in 

 mind when we have a large genus containing a number of well- 

 defined types, around all or many of which cluster a series of 

 closely related forms, that the term species be restricted to the 

 former, while the latter are classed as subspecies, there ought in 

 most cases to be no very great difficulty. In such an arrange- 

 ment the amateur and the popular naturalist, as well as the 

 student of geographical distribution in its wider and more 

 important sense, can confine himself to the species, while the 

 specialist can busy himself about the subspecies, or even the 

 " sub-subspecies." 



Possibly a greater latitude may have to be allowed to the 

 students of the smaller mammals, such as the rodents, in which 

 species may have to be based on slighter differences than 

 are taken cognisance of in the case of the larger forms. 

 Although perfect uniformity would be desirable, it is by no 

 means absolutely essential that the same standard of distinction 

 should be applied to all the groups. 



As might have been expected. Dr. Merriam, one of the great 

 champions of "splitting," has not allowed Mr. Roosevelt's 

 challenge to pass in silence. And he has published a reply in 

 Science of May 14, under the title of " Suggestions for a New 

 Method of Distinguishing between Species and Subspecies." 

 And here a moment's digression may be made to compliment 

 both writers on the good feeling displayed in their criticisms — 

 a marked contrast to some Transatlantic scientific disputations. 

 Dr. Merriam states that hitherto he has taken the following as 

 the distinction between species and subspecies, viz. that" Forms 

 known to intergrade, no matter how different, must be treated 

 as subspecies and bear trinomial names ; forms not known to 

 intergrade, no matter how closely related, must be treated as 

 full species and bear binomial names." This is, of course, one 

 of those hard-and-fast rules which look very nice on paper, but 

 are not consonant with nature's system ; for it is merely an 

 accident whether the intermediate link is still existing, or has 

 died out at a more or less remote epoch. In his new com- 

 munication Dr. Merriam, for the first time, recognises the un- 

 importance of the survival or extinction of the connecting link, 

 and views with approval the proposal that our choice of bi- 

 nomial or trinomial nomenclature is to be governed by the 

 degree of differentiation rather than intergradation. He expresses 

 his new view as follows, viz. "In my judgment, forms which 

 differ only slightly should rank as subspecies even if not known 

 to intergrade, while forms which differ in definite, constant arid 

 easily recognised characters should rank as species even if known 

 to intergrade." 



It was not, of course, to be expected that Dr. Merriam 

 would forthwith strike his fl^, and admit that Mr. Roosevelt 

 is right and himself wrong, but the giving up of the bugbear 

 " intergradation "asa factor in thequestion at issueis undoubtedly 

 a great point gained on the side of the " lumpers." It is, in 

 fact, a clear admission that both species and subspecies are pure 

 abstractions in the case of large genera, and that whether an 

 animal is called one or the other is simply a matter of con- 

 venience. This being so, we may hope for the future to hear 

 no more about such a creature being a " good " species. 



The question of the distinction between species and sub- 

 species is undoubtedly one bristling with difficulties, and it is 

 therefore one which in many cases is incapable of being de- 

 finitely settled by an individual opinion. Although personally 

 convinced of the advisability of using specific names in a wide 

 sense, and employing trinomials for the designation of the nearly 

 related forms, it may be suggested that an international com- 

 mittee of zoologists should be formed to discuss the question 



