Some of my statements in regard to the ancestry or 

 relations of the various groups may doubtless appear very 

 dogmatic. They are not intentionally so, and have been 

 put in a positive form simply to avoid circumlocution and 

 the constant use of "probably," "possibly," and similar 

 expressions. 



It is obvious that a classification such as this can only be 

 in a limited sense original. It must of necessity agree in 

 many respects with older schemes, amongst which the well- 

 known diagrams of Professor Haeckel, published first in 

 1866, * are the most notable of those in a tree-like form. 



In working out the details of the table many books have 

 been consulted, and I have tried to incorporate the views of 

 the latest authorities so far as they commended themselves 

 to my judgment. I may expressly mention the extensive use 

 that has been made of various books and papers by Huxley, 

 Ray Lankester, Moseley, Haeckel, Glaus, and others; and 

 particularly of that invaluable work, Balfour's Treatise on 

 Comparative Embryology, 



No one can be more profoundly impressed than I am 

 with the temporary nature of such a table as this. The 

 rapid advances of biological investigation will probably very 

 soon necessitate additions and corrections to any such phylo- 

 genetic scheme. The utmost that can be desired is that it 

 should express diagrammatically the present state of know- 

 ledge as to the natural classification of animals. 



W. A. HERDMAN. 



University College, 



Liverpool, Januanj, 1885. 



* Generelle Morphologic. See also Anthwpogenie, etc., Leipzig, 1877, 

 and Naturliche Schopfungsgeschichte, Berlin, 1879. 



