7'ra7isactions. 25 



perhaps the most important point of all. The differences 

 between two allied species may be of a minute and scarcely 

 visible character, and yet if those diflFerences lead to the flowers 

 being visited by utterly different insects, these two species are as 

 much isolated from one another as if the broad Atlantic lolled 

 between them. Mutual crossing is impossible, and each species 

 is perfectly free to follow any line of variation which it chooses. 

 Isolation of this kind is, as we can see from the study of island 

 farms, a most fruitful cause of new species. Hence the import- 

 ance of a study of insect visitors is enormous, and it is astonish- 

 ing to find that whilst there are probably several Imndred 

 botanists who can name any British plant presented to them, 

 practically nothing has been done in this direction. 



Unfortunately, every little detail requires the most tedious 

 and exasperating work in the field, and the habits and customs 

 of our bees and flies have been even less studied than those of our 

 plants. Any of our members who begin this branch will, how- 

 ever, find a field almost untrodden, and, however, superficial the 

 instances given may be, T hope some may be induced to under- 

 take this most fascinating yet bewildering and difficult branch of 

 botany. In this hope, I recommend them to begin with a care- 

 ful study of Herbert Spencer, that they may be delivered from the 

 haunting fear of Weismaimism, which has long been dead and 

 buried on the Continent, but occasionally returns in this countiy 

 to life. I must also recommend them to study Miiller's " Fertilisa- 

 tion of Plants," and to read carefully and critically Professor 

 Henslow's " Floral Structures." They will find that I am very 

 deeply indebted to all these authors, and to Mr Grant Allen for 

 the theoretical part of this paper. 



2. Trade l^okens. 



By Mr Philip Sulley, F.R.Hist.S. 



Mr Sulley in the first place made some general remarks 

 regarding trade tokens, pointing out that while the whole coinage 

 on record from Anglo-Saxon times to tiie present did not exceed 

 a thousand different specimens, the trade tokens issued at various 

 tinaes exceeded sixtv thousand. The cause of the issue of sucli 



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