PEDIGREES. 167 



The interest to the world at large attached to 

 the pedigree of an individual of our own species, 

 however distinguished or popular he may be at 

 any particular moment, is never very deep or 

 widespread, and but rarely of any very great 

 importance or value save to the individual con- 

 cerned. But with the lower animals this is not 

 so. Whatever we can gather of the life history 

 of an animal, of its ancestors and its relations to 

 other forms, is knowledge cf universal interest 

 and profit received with gladness by men of all 

 tongues. Indeed the piecing together of the 

 pedigrees of animals is now one of the most 

 important considerations of men of science. 



The present and succeeding chapters of this 

 little book will be devoted to a brief presentation 

 of the main facts which have been discovered 

 concerning the ancestry of that very ancient 

 house of cold-blooded vertebrates — the fishes, 

 and the nature of the consequent grouping 

 together of the various forms which has re- 

 sulted therefrom. 



For the sake of clearness we shall begin not 

 with the most primitive of all known fishes, nor 

 with forms undoubtedly primitive and of great 

 antiquity, but concerning whose affinities there is 

 much dispute. For concerning these last some 

 hold that they bear the stamp of so lowly a char- 

 acter that they are probably to be regarded as 

 forms yet lower in the scale than the fishes them- 

 selves. Eather we shall choose as a starting-point 

 the more specialised descendants of these which re- 

 present some of the most lowly of the living fishes, 

 and about the primitive nature of which all are 



