48 



Dr. Fiusch and I can agree to consider them good and true species, or merely 

 local varieties of Nestor meridionaUs, so long as they can be sufficiently dis- 

 tinguished. On no subject, probably, are the views of modern zoologists more 

 divided, than on the question of what constitutes a species and what a variety. 

 The definition of the term "species" is, after all, purely arbitrary, and is 

 determined in a great measure by the individual opinion of every naturalist. 

 Extreme views are held on both sides, one class of natui'alists contending that 

 it matters not how small the difference is between two allied species, provided 

 it be constant, while there is a growing tendency among another class to group 

 together a large number of slightly different species, usually considei"ed dis- 

 tinct, as merely local or climatic varieties of one typical form. " Between these 

 opposite views," to quote from a high authority, "there is certainly ample room 

 for every shade of opinion. Every naturalist, indeed, has his own views on 

 the matter. The fact is, that the amount of difference requisite to establish 

 specific distinctness between two sets of individuals is, as has been well main- 

 tained by an eminent writer whose views are adverse to the real existence of 

 species, a matte?- of opinion, and we should therefore be very careful in blaming 

 writers whose ideas on this point may be at variance with our own." 



Of the two classes of " lumpers and splitters," as they have been respec- 

 tively termed, numerous examples might be given from the ranks of the best 

 ornithologists. As an instance of the former, however, I may mention that 

 Dr. Fiusch has united, under Comcnos jjertinax, the species named C. ceruginosus, 

 C. chrysogenys, G. xantholcemvs, C. ocularis, and C. chrysophrys. {Papagien, 

 Yol. i., p. 506). It is not for me to say that a naturalist of Dr. Finsch's 

 experience is wrong in this decision ; but we have it, on the authority of Mr. 

 Sclater, Secretary to the Zoological Society, that two of these forms, Conurus 

 xantliolcemus and G. chrysophrys, "living side by side in the Society's gardens, 

 are very distinct species and certainly not to be confounded together," [Proc. 

 Zool. Soc, 1867, p. 588.) 



" Many years ago," says Mr. Darwin, " when comparing and seeing others 

 compare, the birds from the closely neighboui-ing islands of the Galapagos 

 Archipelago, both one with another, and with those from the American main- 

 land, T was much struck how entirely vagiie and arbitrary is the distinction 

 between species and varieties. "' * * Even Ireland has a few animals, now 

 generally regarded as varieties, but which have been ranked as species by some 

 zoologists. Several most experienced ornithologists consider our British red 

 grouse as only a strongly marked race of a Norwegian species, whereas the 

 greater number rank it as an undoubted species peculiar to Great Britain." 

 He further states that few well marked and well known varieties can be named 

 which have not been ranked as species by at least some competent judges, and 

 he summarises thus : — " Certainly no clear line of demarcation has as yet been 

 drawn between species and sub-species — that is, the forms which in the opinion 



