Chapter II: General Anatomical Characters 7

I. Tegumentary Structures 7

Hair, 7; Colour, 8; Scales, etc., 11; Nails, claws, and
hoofs, 12; Odour-secreting glands, 12.

II. Dental System 13

Teeth, 13; Structure of teeth, 13; Development of teeth, 15;
Forms of teeth, 17; Succession of teeth, 19; Arrangement,
homologies, and notation of teeth, 21; Dental formulæ,
25; Modifications of teeth in relation to function, 28;
Taxonomy, 30; Trituberculism, 30.

III. The Skeleton 33

Definition, 33; Axial skeleton, 34; Skull, 34; Vertebral
column, 39; Cervical vertebræ, 41; Dorsal vertebræ, 42;
Lumbar vertebræ, 42; Sacral vertebræ, 43; Caudal vertebræ,
43; Sternum, 44; Ribs, 44; Appendicular skeleton, 46;
Anterior limb, 46; Shoulder-girdle, 46; Brachium and
Antebrachium, 47; Manus, 48; Carpus, 48; Metacarpus and
Phalanges, 49; Posterior limb, 50; Pelvic girdle, 50; Thigh
and Leg, 51; Pes, 52.

IV. The Digestive System 53

General considerations, 53; Mouth, 54; Salivary glands, 55;
Stomach, 57; Intestinal canal, 59; Liver, 60.

V. Circulatory, Absorbent, Respiratory, and Urinary Systems 63

Blood, 63; Heart, 63; Lymphatic vessels, 65; Ductless
glands, 65; Nostrils, 66; Trachea, 67; Larynx, 67;
Diaphragm, 67; Lungs, 68; Air-sacs, 68; Urinary Organs, 69;
Bladder, 69.

VI. Nervous System and Organs of Sense 69

Brain, 69; Nerves, 71; Sense of touch, 72; Taste and smell,
72; Sight, 72; Hearing, 73.

VII. Reproductive Organs 74

Testes, 74; Penis, 74; Ovaries and oviduct, 75; Mammary
glands, 75; Secondary sexual characters, 76; Placenta, 76.

CHAPTER III

ORIGIN AND CLASSIFICATION OF THE MAMMALIA 82

Origin, 82; Classification, 84; Table of orders and
families, 88.

CHAPTER IV

GEOGRAPHICAL AND GEOLOGICAL DISTRIBUTION 93

I. Geographical Distribution 93

Zoological regions, 96; Palæarctic region, 97; Ethiopian
region, 98; Oriental region, 100; Celebes, 102; Nearctic
region, 102; Neotropical region, 103; Aquatic mammals, 104.

II. Geological Distribution 107

Sequence of strata, 107; Mesozoic mammals, 109;
Multituberculata, 109; Polyprotodont types, 113; Tertiary
mammals, 115.

CHAPTER V

THE SUBCLASS PROTOTHERIA OR ORNITHODELPHIA 117

General characters, 117. _Family_ ORNITHORHYNCHIDÆ, 119;
_Ornithorhynchus_, 119. _Family_ ECHIDNIDÆ, 124; _Echidna_,
125; _Proechidna_, 126; Fossil species, 127.