OCR Text |
Show 388 MR. G. E. H. BARRETT-HAMILTON ON [Apr. 3, with an apology for the work in which he is engaged. So long as the field of enquiry be entomology, the attempt to describe and classify local variations, and to gain some knowledge of the guiding principles which underly them, is regarded with respect. If, on the other hand, a zoologist attempts to institute a similar inquiry respecting mammals, he is regarded with suspicion, or often as a mere species-monger who wishes to burden the compilers of local faunas with the names of a number of forms, the status and relationships of which only a longstudy will help them to thoroughly understand. Vet modern investigations have clearly shown the existence of a rich crop of local variations amongst the Mammalia, not less worthy of study than those found amongst the Lepidoptera or Mollusca, and which I hold it to be clearly the business of systematic zoology not only to describe and to arrange, but to name. In treating a species well known and long recognized, such as 31ussylvaticus, I prefer to regard as subspecies all forms which can be identified as in any way phases or representative modifications of the original type as known to Linnaeus. The method, so much in favour in America, whereby all forms which intergrade are looked upon as subspecies, and all those which do not are regarded as species, has much to recommend it; but the si nip1 e ascertainment of the fact that intergradation does, or does not, occur alone implies a greater knowledge and an ampler series of specimens than we, in the Old World, possess of many of the very commonest mammals. Further, by its unavoidable multiplication of species it obscures the relationship of kindred species and genera, and necessitates the formation of new genera or subgenera to include the various groups of new species and subspecies. Under this system many, if not all, of our time-honoured Old World species would be raised to the rank of full genera-a contingency which may be eventually necessary, but which it seems desirable to postpone to as late a date as possible. On the other hand, the system used in this paper has the advantage of roughly indicating the relationship of the forms dealt with. W e do not, however, thereby escape from the difficulty that these forms are of widely different degrees of distinctness. For instance, whereas some of our western subspecies approach each other closely, even in their extreme phases, and will probably be found to intergrade freely, there are others, such as 3Ius sylvaticus princeps or 31. s. draco, which, even if they be proved to intergrade, are in their extreme phases highly distinct and at once recognizable. Some forms there are, however, which, having been long separated from the parent form, have become so differentiated that the most stubborn disregarder of local variations could not consider them to be identical with 31. s. tgpicus. Such is M. argenteus of Japan. To it accordingly, lest m y judgment should be found erring in allying it too closely with M. sylvaticus, I here accord full specific rank. A further advantage may be claimed for the method which is |