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THE PRESIDENT'S ADDRESS. 

 SOME FACTORS OF EVOLUTION IN SPONGES. 



By Arthur Dendy, D.Sc, F.R.S. 



Professor of Zoology in the University of London. 

 {Delivered February 22nd, 1916.) 



There is, I believe, at the present day, an unfortunate tendency 

 on the part of a certain school of biologists to underrate the 

 importance of systematic zoology as compared with other 

 branches of biological investigation. Professor Bateson, indeed, 

 has expressed the opinion * that biologists in general " have 

 abandoned systematics altogether," but our estimate of the cor- 

 rectness of this assertion must obviously depend upon how we 

 choose to define the term "biologist." Some of us think that the 

 science of biology includes the study of the whole of the organic 

 world in all its aspects, and that the systematic description and 

 arrangement of plants and animals constitutes an indispensable 

 part of the foundation upon which all biological theory must 

 be based. Indeed, I would go further, and even say that no 

 biologist without some considerable experience of systematic 

 zoology or botany is really competent to form a judgment on 

 such problems as the nature and origin of species and varieties. 

 I have, it is true, little sympathy with the systematist whose 

 sole object is to name his specimens and put them away on the 

 appropriate shelves in his museum, in the hope, perhaps, of 

 ultimately gathering together a larger collection of " species " 

 than his neighbour. The labours of such a one, except in so far 

 as they may afford material for the investigations of those who 

 are better able to make use of it, hardly rise above the level 

 of the efforts of the schoolboy who amuses himself by collecting 

 tradesmen's labels. Such a man, indeed, has no right tO call 



* Problems of Genetics, 1913, p. 10, 



