ØRN 
Page. 
Rarlvekistory - - +54 1) 
Names et SER 12 
Normal Distribution . . . 15 
Resorts and Habits in Nor 
makavearss. 2: le. 117 
Prolitic Years . . 2... . 18 
Contemporarily Prolific 
Years in Other Species. . 20 
Breeding Conditions in a 
Broktcmearu- 1. 2 25 
The Causes of the Migra- 
UGAE. 16 SE 31 
Centres of the Migrations 83 
The Direction and Extent 
of the Migrations 35 

Page. 
The Frequency and Dura- 
tion of the Migrations . . 
Examples of Migratory 
Mears ho ke 
Nature and Habits during 
Migration 
The Lemmings and Water 
Diseases 
*Lemming-Fever” . . ... 
Great Migratory Years... 
Variettes us 


(Printed 9th April 1895.) 
37 
