254 [October, 



natural separation, the other that they are scarcely more than artificial groupings. 

 distinct enough indeed in most caBCS, but not in all. The best opinion appears to be, 

 that while specific distinctions are (for all practical purposes of a catalogue) generally 

 absolute, there are certain groups in all Orders of Zoology where absolute specific 

 distinctions do not exist, as, for instance, the willows or brambles of the botanist, 

 the willow warblers and their allies, or the titlarks among birds, the ammonites or 

 terebratulas among fossil nioUusca, and the pectens among recent ones, not to mention 

 the groups in our own collections which, as we entomologists shall have no difficulty 

 in recollecting, present similar difilculties among the Affrotes, the SciaphilcB, the 

 ColeophorcB, and other genera. Now, it is especially by the study of these groups 

 that we hope to increase our knowledge of the methods of Creation, and a 

 satisfactory system of classification of them will be of gi-eat service in this study. 

 If it be true, then, that even specific distinctions are in certain cases not absolute, 

 but only relative, we must again fall back on custom to help us out in the difficulty, 

 taking certain well known named standard forms as distinct species for purposes of 

 classification. And it is easy, without introducing any fresh want of uniformity, to 

 indicate, if it be thought advisable, the more artificial nature of such distinctions 

 by some peculiarity in the type used for those particular names in the catalogue. 



Finally, the naming of varieties has lately been proceeding at a rate so pro- 

 digious, as apparently to have excited in the bosorji of rival classifiers a spirit of 

 violent opposition. No doubt, this pursuit, which is lamentably easy, can be carried 

 to an excess. But the study of variation and aberration (to use terms which are 

 intended to express two different lines of effect of the same force) is one of sucli 

 extreme interest and value to the student of Nature, that the utmost pains should 

 be taken to obtain a proper classification and naming of varieties and aberrant forms. 

 Perhaps it may be allowed to treat somewhat further of this subject in a subsequent 

 paper, as it does not seem to affect the matter now in hand. 



To sum up the results of this paper — 



1. A catalogue cannot be made to represent fully the Natural Order. Its one 

 object should, therefore, be to provide a handy means of reference, for which purpose 

 the utmost obtainable degree of finality, both of Order and Nomenclature, is essential. 



2. Such finality of Order is to be obtained by selecting once for all a well 

 known catalogue, and allowing no deviations from the order in this catalogue, 

 except where it is proved that a species or group is placed in an absolutely incon- 

 gruous neighbourhood, and that there is a suitable place for it elsewhere. 



3. Such finality of Nomenclature is not to be found by the application of the 

 canon of priority alone, but by supplementing, or rather curtailing, that canon by 

 placing a limit beyond which it shall not operate, and by refusing to recognise any 

 change in favour of a less known name, when there is any doubt as to the earlier 

 description being applicable, or, if applicable, being too inclusive. 



4. In cases where specific distinctions are doubtful, keep accepted standards, the 

 doubtfulness of which may, however, be indicated by some accepted peculiarity 

 of print. 



The writer has two objects in publishing this paper. First, to invite comments, 

 and thus endeavour to ascertain whether any further canons may be needed to 

 procure the great desideratum of a standard catalogue. And next, to induce the 

 powers that be in Britain to take counsel with the powers that be elsewhere, and to 

 apply the canons at the very earliest opportunity. 



15, Buckingliam Place, Brighton : 

 June 3rd, 1890. 



