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 Am- 

 nion Animals into Two Main Lines : on the one side, Reptiles 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 Animals 

 (Monotremata, or Ornitlwdelpliia). The Extinct Primitive Mammals 

 (Pro-mammalia) and the Extant Beaked Animals (Ornithostoma) . 

 Seventeenth Ancestral Stage : Pouched Animals (Narsupialia, or Didel- 

 phia). Extinct and Extant Pouched Animals. Their Intermediate 

 Position between Monotremes and Placental Animals. Origin and 

 Structure of Placental Animals (Placentalia, or Moiwdelphia) . Forma- 

 tion of the Placenta. The Deciduous Embryonic Membrane (Decidua). 

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

 Decidna (yera, serotina, reflexa) in Man and in Apes. Eighteenth 

 Stage: Semi-apes (Prosimiai). Nineteenth Stage: Tailed Apes (Meno- 

 cerca). Twentieth Stage : Man-like Apes (Antliropoides). Speechless 

 and Speaking Men (Mali. Homines). 



** A century of anatomical research brings us back to the conclusion of 

 Linnaeus, the great lawgiver of systematic zoology, that man is a member 

 of the same order as the apes and lemurs. Perhaps no order of mammals 

 presents us with so extraordinary a series of gradations as this, leading us 

 insensibly from the crown and summit of the animal creation down to 

 creatures from which there is but a step, as it seems, to the lowest, smallest, 

 and least intelligent of the placental mammalia. It is as if nature herself 



