# THE EVOLUTION OF MAN

A POPULAR SCIENTIFIC STUDY

## by
ERNST HAECKEL

Volume I
HUMAN EMBRYOLOGY OR ONTOGENY

Translated from the Fifth (enlarged) Edition by Joseph McCabe
[Issued for the Rationalist Press Association, Limited]
WATTS & CO.
17 Johnson's Court, Fleet Street, London, E.C.
1912

CONTENTS OF VOLUME I
LIST OF ILLUSTRATIONS
GLOSSARY
TRANSLATOR'S PREFACE
TABLE: CLASSIFICATION OF THE ANIMAL WORLD

Chapter I. THE FUNDAMENTAL LAW OF ORGANIC EVOLUTION
Chapter II. THE OLDER EMBRYOLOGY
Chapter III. MODERN EMBRYOLOGY
Chapter IV. THE OLDER PHYLOGENY
Chapter V. THE MODERN SCIENCE OF EVOLUTION
Chapter VI. THE OVUM–THE AMŒBA
Chapter VII. CONCEPTION
Chapter VIII. THE GASTRÆA THEORY
Chapter IX. THE GASTRULATION OF THE VERTEBRATE
Chapter X. THE CŒLOM THEORY
Chapter XI. THE VERTEBRATE CHARACTER OF MAN
Chapter XII. THE EMBRYONIC SHIELD–GERMINATIVE AREA
Chapter XIII. DORSAL BODY–VENTRAL BODY
Chapter XIV. THE ARTICULATION OF THE BODY
Chapter XV. FŒTAL MEMBRANES AND CIRCULATION

LIST OF ILLUSTRATIONS
Fig. 1. The human ovum
Fig. 2. Stem-cell of an echinoderm
Fig. 3. Three epithelial cells
Fig. 4. Five spiny or grooved cells
Fig. 5. Ten liver-cells
Fig. 6. Nine star-shaped bone-cells
Fig. 7. Eleven star-shaped cells
Fig. 8. Unfertilised ovum of an echinoderm
Fig. 9. A large branching nerve-cell
Fig. 10. Blood-cells
Fig. 11. Indirect or mitotic cell-division
Fig. 12. Mobile cells
Fig. 13. Ova of various animals
Fig. 14. The human ovum
Fig. 15. Fertilised ovum of hen
Fig. 16. A creeping amœba
Fig. 17. Division of an amœba
Fig. 18. Ovum of a sponge
Fig. 19. Blood-cells, or phagocytes
Fig. 20. Spermia or spermatozoa
Fig. 21. Spermatozoa of various animals
Fig. 22. A single human spermatozoon
Fig. 23. Fertilisation of the ovum
Fig. 24. Impregnated echinoderm ovum
Fig. 25. Impregnation of the star-fish ovum
Figs. 26–27. Impregnation of sea-urchin ovum
Fig. 28. Stem-cell of a rabbit
Fig. 29. Gastrulation of a coral
Fig. 30. Gastrula of a gastræad
Fig. 31. Gastrula of a worm
Fig. 32. Gastrula of an echinoderm
Fig. 33. Gastrula of an arthropod
Fig. 34. Gastrula of a mollusc
Fig. 35. Gastrula of a vertebrate
Fig. 36. Gastrula of a lower sponge
Fig. 37. Cells from the primary germinal layers
Fig. 38. Gastrulation of the amphioxus
Fig. 39. Gastrula of the amphioxus
Fig. 40. Cleavage of the frog's ovum
Figs. 41–44. Sections of fertilised toad ovum
Figs. 45–48. Gastrulation of the salamander
Fig. 49. Segmentation of the lamprey
Fig. 50. Gastrulation of the lamprey
Fig. 51. Gastrulation of ceratodus
Fig. 52. Ovum of a deep-sea bony fish
Fig. 53. Segmentation of a bony fish
Fig. 54. Discoid gastrula of a bony fish
Figs. 55–56. Sections of blastula of shark
Fig. 57. Discoid segmentation of bird's ovum
Figs. 58–61. Gastrulation of the bird
Fig. 62. Germinal disk of the lizard
Figs. 63–64. Gastrulation of the opossum
Figs. 65–67. Gastrulation of the opossum
Figs. 68–71. Gastrulation of the rabbit
Fig. 72. Gastrula of the placental mammal
Fig. 73. Gastrula of the rabbit
Figs. 74–75. Diagram of the four secondary germinal layers
Figs. 76–77. Cœlomula of sagitta
Fig. 78. Section of young sagitta
Figs. 79–80. Section of amphioxus-larvæ
Figs. 81–82. Section of amphioxus-larvæ
Figs. 83–84. Chordula of the amphioxus
Figs. 85–86. Chordula of the amphibia
Figs. 87–88. Section of cœlomula-embryos of vertebrates
Figs. 89–90. Section of cœlomula-embryo of triton
Fig. 91. Dorsal part of three triton-embryos
Fig. 92. Chordula-embryo of a bird
Fig. 93. Vertebrate-embryo of a bird
Figs. 94–95. Section of the primitive streak of a chick
Fig. 96. Section of the primitive groove of a rabbit
Fig. 97. Section of primitive mouth of a human embryo
Figs. 98–102. The ideal primitive vertebrate
Fig. 103. Redundant mammary glands
Fig. 104. A Greek gynecomast
Fig. 105. Severance of the discoid mammal embryo
Figs. 106–107. The visceral embryonic vesicle
Fig. 108. Four entodermic cells
Fig. 109. Two entodermic cells
Figs. 110–114. Ovum of a rabbit
Figs. 115–118. Embryonic vesicle of a rabbit
Fig. 119. Section of the gastrula of four vertebrates
Figs 120. Embryonic shield of a rabbit
Figs. 121–123. Dorsal shield and embryonic shield of a rabbit.
Fig. 124. Cœlomula of the amphioxus
Fig. 125. Chordula of a frog
Fig. 126. Section of frog-embryo
Figs. 127–128. Dorsal shield of a chick
Fig. 129. Section of hind end of a chick
Fig. 130. Germinal area of the rabbit
Fig. 131. Embryo of the opossum
Fig. 132. Embryonic shield of the rabbit
Fig. 133. Human embryo at the sandal-stage
Fig. 134. Embryonic shield of rabbit
Fig. 135. Embryonic shield of opossum
Fig. 136. Embryonic disk of a chick
Fig. 137. Embryonic disk of a higher vertebrate
Figs. 138–142. Sections of maturing mammal embryo
Figs. 143–146. Sections of embryonic chicks
Fig. 147. Section of embryonic chick
Fig. 148. Section of fore-half of chick-embryo
Figs. 149–150. Sections of human embryos
Fig. 151. Section of a shark-embryo
Fig. 152. Section of a duck-embryo
Figs. 153–155. Sole-shaped embryonic disk of chick
Figs. 156–157. Embryo of the amphioxus
Figs. 158–160. Embryo of the amphioxus
Figs. 161–162. Sections of shark-embryos
Fig. 163. Section of a Triton-embryo
Figs. 164–166. Vertebræ
Fig. 167. Head of a shark-embryo
Figs. 168–169. Head of a chick-embryo
Fig. 170. Head of a dog-embryo
Fig. 171. Human embryo of the fourth week
Fig. 172. Section of shoulder of chick-embryo
Fig. 173. Section of pelvic region of chick-embryo
Fig. 174. Development of the lizard's legs
Fig. 175. Human-embryo five weeks old
Figs. 176–178. Embryos of the bat
Fig. 179. Human embryos
Fig. 180. Human embryo of the fourth week
Fig. 181. Human embryo of the fifth week
Fig. 182. Section of tail of human embryo
Figs. 183–184. Human embryo dissected
Fig. 185. Miss Julia Pastrana
Figs. 186–190. Human embryos
Fig. 191. Human embryos of sixteen to eighteen ays
Figs. 192–193. Human embryo of fourth week
Fig. 194. Human embryo with its membranes
Fig. 195. Diagram of the embryonic organs
Fig. 196. Section of the pregnant womb
Fig. 197. Embryo of siamang-gibbon
Fig. 198. Section of pregnant womb
Figs. 199–200. Human fœtus–placenta
Fig. 201. Vitelline vessels in germinative area
Fig. 202. Boat-shaped embryo of the dog
Fig. 203. Lar or white-handed gibbon
Fig. 204. Young orang
Fig. 205. Wild orang
Fig. 206. Bald-headed chimpanzee
Fig. 207. Female chimpanzee
Fig. 208. Female gorilla
Fig. 209. Male giant-gorilla

Glossary