PRESIDENTS ADDRESS. 
127 
never been joined to a great continent, or if they have been so they 
have been subsequently submerged, and all their mammals and 
most of their birds destroyed. 
The difference between these fundamentally different kinds of 
islands has been most ably treated of by Wallace in his ‘Island 
Life,’ but so many new facts have been discovered since its 
publication, now more than ten years ago, that the book is somewhat 
out of date. Mr. Wallace is however at present engaged in 
writing a new edition corrected up to date, and I strongly adviso 
every zoologist to buy a copy and study it well. It discusses 
problems of the most profound interest, inasmuch as without some 
knowledge of them modern zoological science is absolutely 
unintelligible. 
VOL. v. 
K 
