MUSEUM OF COMPARATIVE ZOOLOGY. 177 



group.* But, in view of the well-known similar variations presented by our 

 American mink, they seem to rest on very unsatisfactory distinctions, es- 

 pecially as the '" varieties" admitted under some of them cover the differences 

 considered as distinctive of the different species. The general paler color 

 and somewhat smaller size of the southern forms f is paralleled by similar 

 differences in specimens of the American animal from the southern portion 

 of its habitat. In view of all these facts, I strongly incline to the opinion 

 that we have here again but one circumpolar and widely dispersed species, 

 with possibly two continental or geographical races that may be more or 

 less easily recognized. Else, as in similar cases previously discussed, we 

 must admit an indefinite number, subject in this respect and in their 

 limitation to the caprice of those authors whose forte is in the description 

 of " supposed new species." J 



11. Gulo luscus Sabine. Wolverine. Dr. De Kay, in his 



* It is a fact especially noteworthy that regions whose Natural History is considered 

 as but partially explored are far richer in species (I refer more especially to mammals 

 and bird?), accepting only such as are currently allowed, than those much longer and 

 more familiarly known. To be assured of this one needs but to compare Southern and 

 Mi Idle Europe with the corresponding parts of Asia, or Eastern and Northern America 

 with Mexico and Central America, adopting as a basis for the comparison only those 

 types or groups widely distributed. This fact is especially illustrated in the Carnivora, 

 as the present family of Mustelidas exemplifies. While distinct types appear in different 

 regions, as some in the warmer latitudes that are not found in the colder, and vice versa, 

 the martens and sables, as well as the minks, under not very different physical con- 

 ditions, far outnumber in Eastern Asia alone, in reputed species, their representatives in 

 Europe. While I would not deny the possibility of this being a fact, the intimate rela- 

 tionship which these several supposed species bear to each other, as well as to the Euro- 

 pean, and the unsatisfactory distinctions on which they are founded, seem to render it 

 extremely improbable. If we extend the comparison to other groups, and to other 

 regions, we constantly meet with cases parallel in all respects to this. This excess 

 of species also almost always happens, in mammals, among those least known, either 

 through their great scarcity or their nocturnal or recluse habits rendering them diffi- 

 cult to obtain. The explanation of this seems to be that new species are not antici- 

 pated to occur in a region that has been for a long time thoroughly explored, while 

 specimens from imperfectly known districts, or of species in groups where the species 

 are supposed to be difficult to distinguish, are most critically examined, and those 

 differing slightly from others previously described — though not more, in many cases, 

 than specimens unquestionably of the same species and obtained at the same locality 

 frequently do — are presumed to represent undescribed species. 



f See Gray's table of comparative measurements of the skulls of his several species 

 Proc. Lond. Zool. Soc, 1865, p. 118. 



I In the mink, as in the marten, it is an interesting fact that the Asiatic specimens 

 bear a stronger resemblance to the American than the European do. According to 

 authors, specimens not unfrequently occur in Japan and portions of Eastern Asia that 

 are hardly distinguishable from average American ones. 

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