the universe, the evolution of species, as we understand the term, is still proceeding. As to what 

 constitutes a " species "is, after all, a mere matter of individual opinion. It is generally admitted 

 that the distinguishing difference must be constant ; but, as to the amount of difference necessary 

 to entitle the form to recognition as a good species, zoologists are and ever will be more or less 

 divided in opinion. Some go to one extreme and some to the other, and all recognise doubtful 

 forms in between.* I have my own views, but am not ambitious to be classed either as a 

 "lumper" or a "splitter." My one concern, as the biographer of the Birds of New Zealand, 

 is to adopt such an arrangement of the forms as will enable the student readily to distinguish 

 them and to learn all that is possible about their natural economy and life-history. This is all 

 the more important, as many of the birds treated of in this work are fast vanishing from the face 

 of the earth, to be seen no more, and to be remembered only by their preserved remains. 



Of the Brown Kiwis, Mr. Eothschild, following the later style of nomenclature, recognises 

 only Apteryx australis australis, and A. australis mantelli, and of the grey-spotted Kiwis 

 also two forms, Apteryx oweni oweni, and A. oweni occidentalism treating Apteryx haasti as 

 quite distinct from the others. It seems to me, however, that the line of demarcation 

 between them is a very uncertain one. Even Mr. Eothschild himself practically admits this ; 

 for a living bird, which I sent him some years ago, presents so many blended characters that 

 he can only get over the difficulty by supposing it to be a wild hybrid! I am disposed, on 

 the contrary, to treat these three last-named species as constituting a second closely related 

 and very natural group. 



In his valuable and very interesting monograph, Mr. Eothschild has paid me the com- 

 pliment of reprinting, in extenso, the life history of Apteryx mantelli, as given in the 'Birds 

 of New Zealand,' and likewise the whole of my notes on Apteryx lawryi, in the ' Transac- 

 tions ' of the New Zealand Institute, uniting the latter species (erroneously as I think), with 

 Apteryx australis. 



Mr. Eothschild' s monograph contains some very interesting observations on the local 

 geographical range of the various species, but the writer falls into the error of extending the 

 range of Apteryx haasti to the North Island. He has since explained, however, through 

 the columns of Nature, that this mistake arose from his having heard of the existence 

 of the species on a wooded islet on the Papaitonga Lake, where these birds, together with 

 Apteryx mantelli and A. oweni, had been placed by myself. 



* In Eidgway's ' List of North American Birds ' trinomial designations are adopted in no less than 160 cases. 

 The author candidly acknowledges that the use of them has caused perhaps the greatest difficulty encountered in the 

 compilation of the catalogue, " it being in many cases very difficult to decide whether a given form should be treated 

 as having passed the varietal stage, and therefore to be designated by a binomial, or whether it is as yet incompletely 

 differentiated and to be subordinated in rank by a trinomial appellation." His contention, however, is that every form 

 whose characteristics bear unmistakably the impress of climatic or local influences, generally less marked towards the 

 habitat of another form with which it thus intergrades, and all forms which certainly intergrade, no matter how widely 

 distinct the opposite forms may appear, together with intergrading forms whose peculiarities are not explained by any 

 known law of variation, should be reduced to subspecific rank. Commenting on this, the Editor of the 'Ibis ' writes : 

 " We cannot deny the advantages of the use of trinomials when strictly limited to such cases as these, and have little 

 doubt that they will ultimately come into general use. But they can only be advantageously employed in countries 

 such as North America and Europe, where large series can be obtained from different localities. In other parts of the 

 world their use would at present be attended by much inconvenience, it being impossible to ascertain in very many 

 cases, from lack of specimens, whether these intergradations exist or not. We may also remark that other authors use 

 trinomials on quite different principles — e.g., Dr. Sharpe, who in his 'Catalogue of Birds' (British Museum) has applied 

 them in some instances even to insular forms (which certainly cannot intergrade) where the slight differences are, in 

 his opinion, not strictly sufficient for specific distinction." I have been unable, however, to find that Dr. Bowdler 

 Sharpe has in any way adopted trinomial nomenclature. He recognises "sub-species" but that, to my mind, is a 

 very different thing. 



