president's address. 719 



in the ProteaceaB is the leaves. While comparatively uniform 

 and highly specialised as regards the structure of their flowers 

 the members of this characteristic order are, as you are aware, 

 distinguished by a great amount of variety in the form and 

 texture of the leaves : it is the foliage, in fact, that is protean 

 much more than the flower ; and the remarkable circum- 

 stance connected with this variability in the leaves is that 

 widely divergent forms of leaf are to be found in members of the 

 order otherwise closely allied. How are such extreme differences 

 to be explained 1 It seems probable, a priori, that a thorough- 

 going investigation would reveal, in some instances at least, a 

 definite usefulness to the plant of the particular form of leaf to be 

 observed ; and perhaps this order is one through which general 

 results on the meaning of various forms of leaves might favourably 

 be attained. There is a peculiarity in the minute structure of the 

 leaves of certain Proteacece (species of Banksia) which they share 

 with the Oleander, that has not been fully accounted for. This 

 consists in the presence, on the under surface, of numerous very 

 minute apertures bordered with hairs, leading into cavities in the 

 substance of the leaf — the stomata being entirely or almost 

 entirely confined to these cavities, instead of being dotted over 

 the general surface. Whether, as has been conjectured, the 

 object of this arrangement is to prevent the stomata from being 

 clogged by excessive moisture, transpiration thus being seriously 

 interfered with, remains to be determined : it seems unlikely, 

 taking into account the circumstances under which the Banksias 

 now live, that any such special modification to provide against 

 excess of moisture is required. 



The zoologist has before him in Australia a very extensive field. 

 Leaving out of account such departments of his subject as can 

 equally well be dealt with in other parts of the world, there are 

 many themes for dealing with which he has special advantages 

 owing to his position in Australia. Let me briefly direct your 

 attention to a few of these. 



The Protozoa are so cosmopolitan in their distribution that they 

 do not display very marked geographical features. Most of the 



