5, 



CONTENTS, 



Preface i 



Contents 3 



Maps Illustrating the Distribution of Species and Sub- 

 species Belonging to the Genera Represented within 

 our Limits in the Eastern United States and Southern 



Canada 7 



Introduction 9 



The Osseus System lo 



Skull, 13; Teeth, 13; Vertebral Column, 15; Pelvis, 15; Ribs, 



15; Sternum, 15; Scapula, 16; Clavicle, 16; Limbs and Feet, 16. 



Anatomical and Physiological Characters in General . 17 



Tegumentary Structures . 18 



Hoofs, Claws and Nails, 18; Hair, 18; Odor-secreting Glands, 

 19. 



Circulatory and Digestive Systems 19 



Heart, 20; Lungs, 21; Blood, 21; Stomach and Intestinal 

 Canal, 22; Liver, 23. < 



Urinary Organs 23 



Reproductive Organs 23 



Mammary Glands 24 



Nervous System and Organs of Sense 24 



Brain, 24; Spinal Chord, 24; Sense of Touch, 24; Sight, 25; 

 Smell, 26; Hearing, 26; Taste, 26. 



Taxonomy and Classification 27 



Subclasses, Orders and Suborders of Living Mammals . . 28 

 Classified List of Mammals of Illinois and Wisconsin . 30 



How TO Estimate the Age of a Mammal 37 



How TO Measure a Mammal 37 



Life Zones 3^ 



Key to the Orders and Families Represented within our 



Limits 41 



Key to the Orders 41 



Key to the Families 41 



Order Marsupialia. Marsupials 49 



Family Didelphiidse. Opossums 51 



3 



