Xl PREFACE. 
He only desires, further, to say that the whole 
of the work has been to him a labour of love, 
and has consequently proved not an arduous 
task, but a delightful occupation. The only suc- 
cess which is desired for it, is that it may commu- 
nicate to its readers, in the same degree, the 
enthusiastic love of Nature to which it owes its 
existence. 
London, September, 1878. 
