viii CONTENTS. 



PAG! 



Lizard-like Parent-form (Protamnion) . First Formation of the 

 Allantois and of the Amnion. Branching of the Amnion Animals 

 in Two Lines : on the one side, Keptiles (and Birds), on the other 

 side, Mammals ... ... ... ... ... ... 107 



CHAPTER XIX. 



THE PEDIGREE OF MAN. 

 IV. FROM THE PRIMITIVE MAMMAL TO THE APE. 



The Mammalian Character of Man. Common Descent of all Mammals 

 from a Single Parent-form (Promammalian). Bifurcation of the 

 Amnion Animals into Two Main Lines : on the one side, Rep- 

 tiles and Birds, on the other, Mammals. Date of the Origin of 

 Mammals : the Trias Period. The Three Main Groups or Sub- 

 classes of Mammals : their Genealogical Relations. Sixteenth 

 Ancestral Stage : Cloacal Animal s (Monotremat a, or Ornithodelphia) . 

 The Extinct Primitive Mammals (Promammalia) and the Extant 

 Beaked Animals (Ornithostoma) . Seventeenth Ancestral Stage: 

 Pouched Animals (Marsupialia, or DidelpTiia) . Extinct and Extant 

 Pouched Animals. Their Intermediate Position between Mono- 

 tremes and Placental Animals. Origin and Structure of Placental 

 Animals (Placentalia, or MonodelpTiia) . Formation of the Pla- 

 centa. The Deciduous Embryonic Membrane (Decidua). Group 

 of the Indecidua and of the Deciduata. The Formation of the 

 Decidua (vera, serotina, reflexa) in Man and in Apes. Eighteenth 

 Stage: Semi-apes (Prosimtce). Nineteenth Stage : Tailed Apes 

 {Menocerca) . Twentieth Stage : Man-like Apes (Anthropoides). 

 Speechless and Speaking Men (Mali. Homines) ,.. ... 140 



CHAPTER XX. 



THE HISTORY OF THE EVOLUTION OF THE EPIDERMIS AND 

 THE NERVOUS SYSTEM. 



Animal and Vegetative Organ-systems Original Relations of these to 

 the Two Primary Germ -layers. Sensory Apparatus. Constituents 

 of Sensory Apparatus : originally only the Exoderm, or Skin-layer ; 

 afterwards, the Skin-covering specialized from the Nerve-system. 

 Double Function of the Skin (as a Covering and as Organ of 



