

PREFACE 



The accompanying Genealogical Table was drawn up in 

 May, 1884, mainly from various partial schemes of classifica- 

 tion which I have been in the habit of using in my lectures 

 for several years ; and a brief description was read in the 

 following December before the Literary and Philosophical 

 Society of Liverpool. While preparing this paper for pub- 

 lication * it occurred to me that in an extended form it 

 might prove serviceable to students of Biology : hence its 

 issue in the present condition. 



As it is intended to be used along with a good text-book, 

 or as a supplement to a course of lectures on Zoology, no 

 attempt has been made to give the characters of the various 

 groups, and the facts of Anatomy and Embryology are 

 only referred to when they indicate the probable course of 

 Phylogeny, Most attention has been devoted to hypothetical 

 ancestral forms which are rarely, if ever, mentioned in the 

 text-books. 



An explanation of the meaning to be attached to the 

 various lines in the table will be found on page 76. The 

 tree-like arrangement is admittedly the best way of repre- 

 senting on a flat surface the affinities of organisms, but it 

 should be remembered that it is after all only a substitute for 

 the model or actual tree, which would much more correctly 

 represent the lines of evolution branching through all the 

 three dimensions of space. 



* Proceedings of the Literary and Philosophical Society of Liverpool 

 for 1884-85. 



