INTRODUCTION 3 



classification. It is commonly supposed, at least I have very 

 often heard it suggested, that naturalists delight in Latin names, 

 and employ them unnecessarily in order to display their own 

 erudition. " Everybody knows what you mean by a perch," 

 say some : " why in the world do you want to call it Perca 

 fluviatilis ? " The answer comes from afar — from the days 

 of Aristotle. The chief obscurity in the luminous discourse 

 upon fishes by that penetrating intellect arises from his use 

 of temporary and local popular names for the different species. 

 It Is because such names not only vary from age. to age, but 

 are applied simultaneously to different creatures In different 

 localities, that we have been driven by necessity to the dead 

 languages — the languages that have passed beyond all change — 

 to secure precise definition. 



Here is an instance of the confusion inevitable in the 

 absence of a scientific standard. Most people know a flounder 

 well enough — at all events, they think they do. But on the 

 south-west coast of Scotland, where flat-fish greatly abound, 

 the true flounder is known as the fluke, and the term flounder 

 is applied popularly to quite a different fish, the plaice. Hence, 

 to avoid confusion, which is the very first step in the advance- 

 ment of knowledge, it has been necessary to give each of these 

 fish a generic and specific name in an unchangeable language. 



Take an instance from the kindred science of ornithology. 

 Among all bird-names there is none, probably, which conveys 

 to British people such a clear, familiar image as that of robin. 

 Even town-bred children, for whom the greenwood, alas ! is 

 too often but an unmeaning phrase, have learnt enough from 

 picture books to attach the title to a little red-breasted bird 

 which spends Christmas with us. But see how different is the 

 idea conveyed by the name of robin to that vast branch of 

 the English-speaking race beyond the Atlantic. The early 

 settler in North America chose to apply this name to a kind 

 of thrush {^Merula migratorid). And, were there no common 

 language wherein ornithologists could confer, science, instead 



