DIFFERENTIATION, MIGRATION, AND MIMICRY. 363 



unobservant and inexact. A century and a half ago, it had not 

 come to be recognised that distribution is, along, of course, with 

 morphology and physiology, a most important factor in deter- 

 mining the facts of biology. It is difficult to estimate what might 

 have been gained in the case of many species, now irreparably 

 lost, had Forster and the other companions of Captain Cook — to 

 say nothing of many previous voyagers — had the slightest con- 

 ception of the importance of noting the exact locality of each 

 specimen they collected. They seem scarcely to have recognised 

 the specific distinctions of the characteristic genera of the Pacific 

 Islands at all, or, if they did, to have dismissed them with the 

 remark, " On this island was found a Flycatcher, a Pigeon, or 

 a Parrot similar to those found in New Holland, but with white 

 tail-feathers instead of black, an orange instead of a scarlet breast, 

 or red shoulders instead of yellow." As we turn over the pages 

 of Latham, or Shaw, how often do we find for locality one of the 

 islands of the South Sea, and even, where the locality is given, 

 subsequent research has proved it erroneous, as though the speci- 

 mens had been subsequently ticketed ; Le Vaillant described many 

 of his South African birds from memory. Thus Latham, after 

 describing very accurately Rhipidura flabellifera, from the south 

 island of New Zealand, remarks, apparently on Forster's authority, 

 that it is subject to variation ; that in the island of Tanna another 

 was met with, with a different tail, &c, and that there was another 

 variety in the collection of Sir Joseph Banks. Endless perplexity 

 has been caused by the Psittacus pygmceus of Gmelin (of which 

 Latham's type is at Vienna) being stated in the inventory as 

 from Botany Bay, by Latham from Otaheite, and in his book 

 as inhabiting several of the islands of the South Seas, and now 

 it proves to be the female Psittacus palmarum from the New 

 Hebrides. These are but samples of the confusion caused by the 

 inaccuracies of the old voyagers. Had there been in the first 

 crew who landed on the island of Bourbon, I will not say a 

 naturalist, but even a simple-hearted Leguat, to tell the artless 

 tale of what he saw, or had there been among the Portuguese 

 discoverers of Mauritius one who could note and describe the 

 habits of its birds with the accuracy with which a Poulton could 

 record the ways and doings of our Lepidoptera, how vastly would 

 our knowledge of a perished fauna have been enriched ! It is 

 only since we learned from Darwin and Wallace the power of 



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