May 14, 1897.] 



SCIENCE. 



755 



A good deal, of course, depends on tlie 

 point of view. Mr. Lydekker as a paleon- 

 tologist and compiler of excellent general 

 works on natural history, and Mr. Roose- 

 velt as a hunter and writer of the best ac- 

 counts we have ever had of the habits of our 

 larger mammals, find it inconvenient and 

 annoying to be confronted by a large num- 

 ber of species. Still, if we examine the 

 writings of theSe authors closely it becomes 

 evident that they usually accept without 

 complaint such species as have been cur- 

 rently recognized by their predecessors. 

 This is only human nature, for are we not 

 always more ready to challenge the an- 

 nouncement of new facts than to suspect 

 those with which we have been long fa- 

 miliar ? 



In my judgment, forms which dififer only 

 slightly should rank as subspecies even if 

 known not to intergrade, while forms which 

 differ in definite, constant and easily recog- 

 nized characters should rank as species even 

 if known to intergrade. 



In a recent article in Science, Mr. 

 Roosevelt protests against the use of the 

 word species where "it has entirely differ- 

 ent weights in different cases," and cites 

 examples of what he considers its proper 

 use. But he forgets a host of cases in 

 which admittedly distinct species are not 

 separated by any such gaps as those he 

 mentions. Mr. Roosevelt, in addition to 

 being a good deal of a mammalogist, is 

 something of an ornithologist, and has 

 made contributions of value to ornitholog- 

 ical literature. He knows, therefore, that 

 in the eastern United States we have two 

 species of falcons belonging to the genus 

 Falco, the Sparrow Hawk and the Duck 

 Hawk, and two species of woodpeckers be- 

 longing to the genus Melanerpes, the Red- 

 headed Woodpecker and the Red-bellied 

 Woodpecker, in both of which cases the 

 species are separated by the kind of gaps he 

 likes. He knows also that we have two 



species of thrushes, the Olive-back and 

 Alice's, and two species of small flycatchers) 

 Traill's and the Least, in both of which 

 cases the species are so much alike that a 

 trained eye is necessary to tell them apart. 

 What will he have us do with these birds ? 

 Shall we unite the two thrushes and the 

 two flycatchers ? If not, how can he recon- 

 cile his theory to the enormous difference in 

 weight of characters that distinguish the 

 species of hawks and woodpeckers, con- 

 trasted with those that distinguish the 

 thrushes and flycatches? The real difii- 

 culty is that in nature some existing species 

 are closely related, while others are widely 

 separated. Still, suppose for the sake of 

 argument that we do attempt to carry out 

 Mr. Roosevelt's suggestion to lessen the 

 number of species by uniting some of those 

 that are more or less closely related, and 

 suppose we select for this purpose two 

 groups of mammals— the bears and coyotes 

 — against whose species he has developed 

 such a violent aversion. If in case of the 

 bears we try to get rid of either the Grizzly 

 (Ursus Jiorribilis), the Barren-ground (i7. 

 richardsoni) , the Yakutat bear (U. dalli), 

 or the huge Alaska Peninsula bear (fj. 

 middendorffi) , and in the case of the coyotes 

 we aim to abolish any one of half a dozen 

 species, as the northeastern Canis latrans, 

 the California C. ochrojms, the Rio Grrande 

 C. microdon or the Mexican C. eagottis, we 

 are at once confronted by the same diffi- 

 culties that would beset Mr. Roosevelt 

 were he to undertake to unite under a 

 smaller number of specific names such 

 birds as the Hermit, Wood, Olive-back, 

 Bicknell's and Wilson's thrushes, or the 

 Warbling, Red-eyed, White-eyed, Hutton's 

 and Philadelphia vireos. These difliculties 

 are of several kinds and involve the solu- 

 tion of such questions as : (1) How many 

 and what species shall be selected as the 

 favored ones with which the others shall be 

 merged? (2) Which of the species to be 



