CHAPTER XIX. 



THE PEDIGREE OF MAN. 



IV. Feom the Primitive Mammal to the Ape. 



The Mammalian Character of Man. — Common Descent of all Mainmalb 

 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 Ornithodelphia) . — 'Ihe Extinct Primitive Mammals 

 (^Promammalia) and the Extant Beaked Animals {Ornitho stoma) . — 

 Seventeenth Ancestral Stage : Pouched Animals {Marsupialia, or Didel- 

 phia). — Extinct and Extant Pouched Animals. — Their Intermediate 

 Position between Monotremes and Placental Animals. — Origin and 

 Structtire of Placental Animals {Placentalia, or Monodelphia) . — Forma- 

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

 — Group of the Indecidua and of the BecidMata. — The Formation of the 

 Decidua {vera, serotina, rejlexa) in Man and in Apes. — Eighteenth 

 Stage: Semi-apes {Prosimice) . — Nineteenth Stage : Tailed Apes {Meno' 

 eerca). — Twentieth Stage : Man-like Apes (Anthropoides). — Speechless 

 and Speaking Men {Mali. Homines). 



** A century of anatomical research brings ns back to the conolnsion 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, 

 »ixd least intelligent of the placental mammalia. It is as if nature iierself 



