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Our Face from Fish to Man.

I. Devonian shark; 2. Upper Devonian air-breathing, lobe-finned fish;
3. Lower Carboniferous amphibian; 4. Permo-Carboniferous reptile; 5. Triassic
mammal-like reptile; G. Cretaceous mammal; 7. Lemuroid primate; 8. Recent
Old World monkey; 9. Chimpanzee; 10. Tasmanian; 11. Roman athlete.

For details see p. xiii.

OUR FACE
FROM FISH TO MAN

c54 ^Portrait Qallery of Our cSAncient ^Ancestors

and Kinsfolk together with a (Concise

history of Our ^Best features

WILLIAM K. GREGORY

Professor of Vertebrate Palaeontology, Columbia University;
Associate in Anthropology and Curator of the Depart-
ments of Ichthyology and Comparative Anatomy,
American Museum of Natural History; Member
of the National Academy of Sciences, etc.

WITH A FOREWORD BY
WILLIAM BEEBE

'With 119 Illustrations

NEW YORK : LONDON

G. P. PUTNAM'S SONS

Cite TXnizkeibxtzktT l^iess
1929

143 if I $

OUR FACE FROM FISH TO MAN

G. P. Putnam's Sons

2SI.H

Made in the United States of America

TO
HENRY FAIRFIELD OSBORN

FOREWORD

BY WILLIAM BEEBE

A foreword to a volume such as the present
one of Dr. Gregory's is as superfluous as would be
the retention of the third eye, the Cyclopean one,
of our ancestors, in the center of our forehead
today. No more wonderful subject for a volume
could be imagined than the evolution of the human
face, and no more competent author than William
K. Gregory. The result seems to me eminently
satisfactory.

If the reader's interest is real but cursory, let
him do nothing but look at the illustrations.
They will ensure a thousand percent interest to
every walk along Fifth Avenue or Regent Street.
If pressure of other interests permits only an hour's
perusal, or complete lack of natural history know-
ledge requires facts to be strained through the
mesh of popular language, read but the preface
and the first few paragraphs of each chapter.

Taken as a whole this is not a "popular" book in

iii

FOREWORD

the sense of a superficial one. The details of
evolution of our eyes, ears, nostrils, mouth — these
are too delicate, too intricate for words of one
syllable. Yet to read and understand this volume
requires no more concentrated attention than the
remembrance of the highest diamond in the ninth
trick, or to what Steel Preferred fell in the Autumn
of 1914.

I advise no Fundamentalist or Anti-Evolutionist
to read it, for if he have no sense of humor he will
not understand it, and if he have, his belief will be
like Dunsany's King who "was as though he never
had been." If with Bergson we believe that the
origin of laughter was cruelty, then an S. P. C. to
something should be formed to prevent the spec-
tacle of a Fundamentalist's face functioning with
the third eyelid of a bird, the ear-point of a deer,
the honorable scars of most ancient gills, and with
his lip-lifting muscles in full action as he sneers
at truth. A moment's thought of these few char-
acters presents a new viewpoint on what we are
wont to call the "lower" animals, for if our third
eyelid were more than a degenerate flap we, like
an eagle, could look straight at the sun; if our ears

could straighten and turn as once, the lives of

FOREWORD

pedestrians would be safer; if the ghosts of gills
were still functional, drowning would be impos-
sible, and if the fang-revealing sneer showed less
degenerate canines, we might have a more physi-
cally wholesome fear of cavilers against the doc-
trine of Evolution.

The impregnable array of facts gleaned through
the centuries of man's intellectual supremacy
proves beyond all question the gradual rise toward
human perfection of the various components of
the face, and this confirms our precious organs of
sense as most noble gateways of the human mind
and soul. Kindness, gentleness, tactfulness, pa-
tience, can flow out through only these channels.
It is a worthy thing to have written a book about
them; it is a fortunate chance to be able to
read it.

PREFACE

According to popular standards of civilized
peoples, men of one's own race and tongue were
called "men," "warriors," "heroes," but people
of other races were "barbarians," "unholy ones,"
"foreign devils." The founder of one's own clan
was often considered to be the son of a deity, while
the barbarians were the descendants of monkeys
or other wild animals. Or the first man was
created perfect, in the image of God. One's own
family, of course, was fairly true to type but sin
had played havoc with the features of other races.
To believe all this was comforting to one's own
"face" in a world where the inferiority complex
occasionally haunted even kings.

Imagine then the effect of telling one-hundred-
percent Americans that they are not the descen-
dants of the god-like Adam but are sons and
daughters of Dryopithecus, or of some nearly allied

genus of anthropoid apes that lived in the Miocene

vii

PREFACE

age, — and that before that they had long tails and
ate grubs and beetles!

If the reader is curious to know the worst he will
find it in these pages. There even his own great-
grandfather— a Jove-like patriarch with ample
beard, piercing eyes and an aquiline nose — will be
subjected to unsparing analysis. It will be shown
how much the proud old gentleman was indebted
to a long line of freebooting forbears that strug-
gled for a precarious living in the sea, on muddy
flats, on the uplands or in the trees — aeons before
Adam delved or Eve span. In detail it will even
be charged that the real founder of the family
was not the powerful settler to whom the king
gave a grant of land extending far back from the
river, but a poor mud-sucking protochordate of
pre-Silurian times; that when in some far-off dis-
mal swamp a putrid prize was snatched by scaly
forms, their facial masks already bore our eyes and
nose and mouth.

Accordingly this little book can hardly expect
much popularity either in Tennessee, where the
very idea of evolution is anathema, or in the metro-
politan strongholds where pithecophobia is still

prevalent and man's complete superiority to the

viii

PREFACE

all too man-like apes is somewhat nervously
stressed.

Nor can the author hope for much favor from
the public, that wants only results and is willing
to spend a billion dollars annually on cosmetics
and safety razors. For this book does not pretend
to tell how to improve one's face but only how and
why one has one.

At best then it can only hold a magic mirror up
to proud man and bid him contemplate his own
image — a composite of an infinitely receding series
of faces, — human, prehuman, anthropoid, long-
snouted, lizard-like, — stretching back into the
shadows of endless time.

CONTENTS

FOREWORD lii

PREFACE vii

PART I. PORTRAIT GALLERY OF OUR ANCIENT
RELATIVES AND ANCESTORS

THE VALUE OF A FACE .... 3

THE BEGINNINGS OF OUR FACE ... 4

THE SHARK'S FACE AND OURS . . .12

THE MASK-FACE OF OUR GILLED ANCESTORS . 20

OUR ANCESTORS COME OUT OF THE WATER . 27

WHAT WE OWE TO THE EARLY REPTILES . 32

THE ONE-PIECE JAW REPLACES THE COMPLEX

TYPE ....... 36

OUR MASK-FACE BECOMES MOBILE . . 40

OUR LONG-SNOUTED ANCESTORS CROWD OUT

THE DINOSAURS ..... 45

BETTER FACES COME IN WITH LIFE IN THE

TREE-TOPS ...... 52

THE ALMOST HUMAN FACE APPEARS . . 64

AT LAST THE " PERFECT " FACE ... 70

PART II. CONCISE HISTORY OF OUR BEST FEATURES

The Bony Framework of the God-like Mask 83

flsh-traps and faces . ... 92

CONTENTS

PAGE

THE FIRST MOUTHS ..... 92

THE BEGINNINGS OF TEETH ... 97

THE PRIMARY JAWS . . . . .102

THE RISE OF THE SECONDARY JAWS AND THEIR

TEETH ....... 106

origin of the mammalian palate . . 118

evolution of the tongue and related

structures . . . . . .123

origin and evolution of the human lips 129

later stages in the history of the teeth 134

conclusions ...... 152

History of the Nose ..... 153

Optical Photography and its Results . 173

the human eyes as instruments of precision 173
the eyes of invertebrates . . .173

origin of the paired eyes of vertebrates 182
origin of the human eyes . . .188

conclusions ...... 200

Primitive Sound Recorders . . . 202

Ancient and Modern Physiognomy . . 220

The Face of the Future .... 240

Looking Backward ..... 245

LITERATURE CITED 247

INDEX 261

ILLUSTRATIONS

PAGE

Our Face from Fish to Man . Frontispiece

1. Devonian shark, Cladoselache; 2. Upper Devonian
air-breathing, lobe-finned fish, Euslhenopteron; 3. Lower
( larboniferous amphibian, Eogyrinus; 4. Permo-Carbon-
iferous reptile, Scymouria; 5. Triassic mammal-like
reptile, Ictidopsis; 6. Cretaceous mammal, Eodclphis;
7. Lcmuroid primate, Propithccus; 8. Recent Old World
monkey; 9. Chimpanzee; 10. Tasmanian; 11. Roman
athlete.

FIGURE

1. — The First Mouths ..... 5

A. Slipper animalcule (Paramaecium) with gash-
like mouth.

B. Jellyfish (Tessera), a two-layered sac with
primitive mouth.

(Both after Parker and Haswell.)

2. — Two Early Stages in the Evolution of a

Head ...... facing 6

A. Flatworm (Planaria), showing head-and-tail
differentiation, including the beginnings of a brain and
of eyes.

B. Sand-flea (Orchestia), showing the interrelations
of eye, brain, mouth, leg-jaws and nerve cord.

(Both after Parker and Haswell.)

3. — The Rise of the Vertebrates in Geologic

Times 9

4. — Some of Our Earliest Known Kinsfolk:
Upper Silurian and Devonian Ostraco-

DERMS ....... 11

A. Pterolcpis. (_After Kiaer.)

B. Tremataspis. (After Rohon.)

xiii

ILLUSTRATIONS

C. Tremataspis. (After Patten.)

D. Pteraspis. (After Powrie and Lankester.)

E. Cephalaspis. (Composite, mainly after Patten.)

5. — The Face of the Most Primitive Living

Shark, Chlamydoselachus anguineus . facing 12
(After Garman.)

6. — Instruments of Precision in the Head of a

Shark, Chlamydoselachus anguineus . . 13

(After Allis.)

Lateral line canals black, bordered with white;
nerves white; muscles streaked; cartilage stippled.

7. — Cartilaginous Skeleton of Head of Shark 17

Comprising braincase, primary upper and lower jaws
and branchial arches.

8.=^Jaw Muscles of Shark (Chlamydoselachus) . 18

Showing the essential similarity of the jaw muscles
to the constrictors of the branchial arches. (Com-
posite drawing based on the data of Allis and Garman.)

9. — Cross-section of the Skull of a Fossil Gan-
oid Fish, Showing the Bone Cells (Osteo-
lepis from the Devonian of Russia) . facing 20
(After Pander.)

10. — The Wedge-shaped Braincase of a Fish,
Acting as a Thrust-Block or Fulcrum
for the Backbone ..... 22

The surface bones of the left cheek region have been
removed to show the base of the skull and the elements
dependent from it on the right side. (Modified from
a drawing of the skull of the Striped Bass by F. A.
Lucas.)

11. — The Facial Armor and Jaws of a Devonian

Lobe-finned Ganoid Fish (Osteolepis) facing 22

(After Pander.)

The skull seen from above.

xiv

ILLUSTRATIONS

ficurk pace

12. — First Claimant to the Line of Ancestry
of THE High Kit Vertebrates. Devonian
"Lobe-fin" (Eu.sthenopteron) . facing 83

(Reconstruction by Bryant.)

13. — Second Claimant to the Line of Ancestry of
the Higher Vertebrates. Devonian Dip-
no an {Dipterus) .... facing 24
(Restoration by Pander.)

14. — Embryos of Modern Lobe-Finned Fish (A)

and Amphibian (B) ..... 26

A. Embryo of Polypterus bichir. (After Budgett.)

B. Embryo of Ambly stoma punctatum. (After S. F.
Clarke.)

15. — One of the Most Primitive Known Amphib-
ians {Eogyrinus) from the Lower Carbon-
iferous of England .... 28

Restoration of skeleton. (Based on data of D. M. S.
Watson.)

16. — Skull of One of the Oldest Known Amphib-
ians (Loxomma allmani) . . . facing 28
(After Embleton and Atthey.)

A. Upper surface.

B. Under side.

17. — Skulls of Lobe-finned Fish and Early
Amphibian, Showing Loss of Opercular
Series in the Latter .... 30

A. Lobe-finned fish, essentially Rhizodopsis. (From
data by Traquair and Watson.)

B. Primitive amphibian, Palwogyrinus. (After
Watson.)

In the primitive amphibians the space formerly
covered by the opercular region was covered by the
tympanum or drum membrane.

ILLUSTRATIONS

FIGURE PAGE

18. — Cross-section of Labyrinthodont Teeth

following 30

A. Lobe-finned Devonian fish (Polyplocodus).
(After Pander.)

B. Primitive amphibian of Carboniferous age
(Loxomma allmani). (After Embleton and Atthey.)

19. — Two Critical Stages in the Early Evolu-
tion of the Skull ..... 33

A. Generalized reptile (Seymouria), retaining the
full complement of amphibian skull elements. The
temporal region, covering the upper jaw muscles, is
still covered with a shell of bone as in primitive am-
phibians and fishes. The otic notch (where the tym-
panum, or drum membrane, was attached) is retained.
(After data of Broili, Watson, Williston.)

B. Primitive theromorph reptile (Mycterosaurus)
with reduced number of skull elements and perforated
temporal roof. The otic notch has disappeared.
(After Williston.)

20. — Skulls of Earlier and Later Mammal-
like Reptiles from South Africa . . 35

A. Scymnognathus, a primitive, more reptile-like
member of the therapsid series.

B. Ictidopsis, a more advanced mammal-like mem-
ber of the same series. Specimens in the American
Museum of Natural History, with data from Broom,
Watson, Haughton.

21. — Progressive Upgrowth of the Dentary
Bone of the Lower Jaw to Form a New
Joint with the Skull .... 37

A. Primitive mammal-like reptile (Scymnognathus).

B. Advanced mammal-like reptile (Ictidopsis).

C. Primitive mammal (Thylacinus) .

22. — Origin of the Interarticular Disc, or
Meniscus, Lying Between the Lower
Jaw and Its Socket in the Skull . . 38

(After Gaupp.)

xvi

ILLUSTRATIONS

FIGURB PAGE

23. — Origin of the Facial Muscles of Man 42

A. Primitive reptile (Labido.iaurun) with continu-
ous bony mask covering skull. (After Willis ton.)
The mask was covered with thick skin without muscles,
as in the alligator.

B. Modern reptile (8 ph morion) with an open or fen-
estrated skull covered with thick, non-muscular skin.
The seventh nerve (heavy black line) is seen beneath
the sphincter colli muscle, a broad band around the
throat. (From Fiirbringer, modified from Ruge.)

C. Primitive mammal (Echidna) in which the
sphincter colli system has grown forward over the
face. (After Ruge.)

D. Gorilla. E. Man. (Both after Ruge.)

24. — Diagram Showing the Chief Branches of

the Facial Nerve ..... 44

A. Gorilla. (After Ruge.)

B. Man. (After Weisse.)

25. — Successive Dominance of the Amphibians,

Reptiles, Mammals and Birds, Man . 46

26. — The Common Opossum, a "Living Fossil"

from the Age of Dinosaurs . facing 46

27. — Skull Parts of Extinct Opossum (Eodelphis)

from the Upper Cretaceous of Montana 48

Superposed on outlines of skull of recent opossum.

28. — Skulls of (A) Advanced Mammal-like Rep-
tile (Ictidopsis) from the Triassic of
South America and of (B) a Modern
Opossum ....... 49

29. — Long-snouted Relatives of Ours from the

Cretaceous of Mongolia ... 50

A. Skull of Deltatheridium pretrituberculare. Nat-
ural size.

xvii

ILLUSTRATIONS

B. Restoration of same.

C. Skull of Zalambdalestes lechei. Natural size.

D. Restoration of same.

(All after Gregory and Simpson.)

30. — The Pen-tailed Tree-shrew of Borneo facing 52

A "living fossil" representing a little-modified sur-
vivor of the Cretaceous ancestors of the Primates.

(Based on photographs and data given by Le Gros
Clark.)

31. — The Spectral Tarsier of Borneo . facing 53

A highly specialized modern survivor of a diversified
group of primates that lived in the Lower Eocene epoch
over fifty million years ago. (Drawn from specimen
preserved in formalin, with aid of data from photo-
graph of a living Tarsius by H. C. Raven.)

32. — Skeleton of a Primitive Fossil Primate
(Notharctus osborni), from the Eocene of
Wyoming ...... facing 54

33. — Skull of a Primitive Primate of the

Eocene Epoch (Notharctus osborni) . . 55

Natural size. (After Gregory.)

34. — Ascending Grades of Faces in the Lower

Primates ...... facing 56

A. Lemur (Lemur variegatus) with fox-like muzzle
and laterally-placed eyes. (After Elliot.)

B. South American Monkey (Cebus capucinus)
with shortened muzzle and widely separated nostrils.
(After Elliot.)

C. Old World Monkey (Lasiopyga pygerythrus) with
nostrils approximated and forwardly-directed eyes.
(After Elliot.)

35. — Top View of the Skull in Representatives
of Six Families of Primates, Showing the
More Forward Direction of the Orbits
in the Higher Forms .... 58
xviii

.ILLUSTRATIONS

A. Fossil lemuroid (Xotharctu.t). Eocene epoch.

B. African Iciniir | .1 rctOCebus).

C. Taraius spectrum, Borneo.

D. Marmoset (Midas).

E. Gibbon (Hylobotea).

F. Chimpanzee (Antlimpnpithecus).

36. — Side View of Skulls of Primates, Showing
Progressive Shortening of the Muzzle,
Downward Bending of the Suborbital
Face and Forward Growth of the Chin 59

A. Eocene lemuroid (Notkarctua).

B. Old World Monkey (Lasiopyga kolbi). (After
Elliot.)

C. Female chimpanzee. (After Elliot.)

D. Man.

37. — Epitome of the Fossil History of Human

and Prehuman Primates. 1927 . . 61

Showing the range in geologic time of the different
groups, their dental formulae, the side view of the
tooth-bearing part of the lower jaw, the lower dental
arch seen from above, and the back part of the lower
jaw.

A. Tree-shrews, represented by jaw of Leipsano-
lestes siegfriedti. (After Simpson. Back part of jaw
from modern tree-shrew Ptilocercus) .

B. Primitive lemuroid, represented by jaw of
Pelycodus frigonodus. (After Matthew.)

C. Proto-anthropoid, represented by jaw of Parapi-
thecus fraasi. (After stereoscopic photograph by J. H.
McGregor.)

D. Proto-anthropoid, represented by jaw of Prop-
liopithecus hasckeli. (After stereoscopic photograph
by J. H. McGregor.)

E. Man-like anthropoid, represented by jaw of
Sivapithecus himalayensis. (After Pilgrim.)

F. Dawn-man, represented by jaw of Eoanthropus
dawsoni. (After A. S. Woodward.)

XIX

ILLUSTRATIONS

G. Primitive man, represented by jaw of Homo

heidelbergensis. (After Schoetensack.)

H. Modern man, represented by jaw of Homo

sapiens. (After Gregory.)

38. — Epitome of the Fossil History of Human and

Prehuman Primates (continued) . . 62

A. Primitive tree-shrew, represented by a left
lower molar of Leipsanolestes.

B. Primitive tree-shrew, represented by left upper
molar of Indrodon.

C. Primitive lemuroid, represented by left lower
molar of Pelycodus. (After Matthew.)

D. Primitive lemuroid, represented by left upper
molar of Pelycodus. (After Matthew.)

E. Proto-anthropoid, represented by left lower
molar of Parapithecus. (From stereoscopic photo-
graph by J. H. McGregor.)

F. Proto-anthropoid, represented by left lower
molar of Propliopithecus. (From stereoscopic photo-
graph by J. H. McGregor.)

G. Proto-anthropoid. Attempted restoration of
upper molar to fit known lower molar.

H. Anthropoid, represented by left lower molar of
Dryopithecus rhenanvs. (From stereoscopic photo-
graph by J. H. McGregor.)

I. Anthropoid, represented by left upper molar of
Dryopithecus rhenanus. (From stereoscopic photo-
graph by J. H. McGregor.)

J. Dawn-man, represented by left lower molar of
Eoanthropus dawsoni. (From stereoscopic photograph
by J. H. McGregor.)

K. Neanderthal man (Homo neanderthalensis),
represented by left lower molar of "Le Moustier."
(From stereoscopic photograph by J. H. McGregor.)

L. Neanderthal man, represented by left upper
molar of "Le Moustier." (From stereoscopic photo-
graph by J. H. McGregor.)

ILLUSTRATIONS

FIGURE PACK

M. Modern man (Homo sapiens), represented by
left lower molar.

N. Modern man (Homo sapiens), represented by
left upper molar.

39. — One of Our Nearest Living Relatives.

Female Chimpanzee and Youm; facing 64

(After Yerkes, from a photograph taken for Mine.
Rosalia Abreu.) The baby chimpanzee was born in
Mme. Abreu's private collection of living primates,
at Quinta Palatine, Havana, Cuba.

(From " Almost Human." Courtesy of the author
and The Century Co.)

40. — Male and Female Chimpanzees . facing 65

(After J. A. Allen, from photographs by Herbert Lang.)

41. — Left Lower Cheek Teeth of Fossil Anthro-
poid (Dryopithecus, B) from India and
Fossil Primitive Man {Eoanthropus, A) from
Piltdown, England .... facing 66

The lower molars of the Piltdown jaw, although
much ground down by wear, show the pure "Dryopi-
thecus pattern" characteristic of recent and fossil
apes.

(A, from photograph by J. H. McGregor; B, after
Gregory and Hellman.)

42. — Fossil Anthropoid and Human Skulls . 68

A. Australopithecus. A young extinct anthropoid,
Bechuanaland, South Africa. (After Dart.)

B. Eoanthropus, England. (After A. S. Woodward
and J. H. McGregor.)

C. Pithecanthropus erectus, Java. (After Dubois.)

D. Neanderthal (La Chapelle-aux-Saints), Europe.
(After Boule.)

E. Talgai, Australia. (After Stewart A. Smith.)

F. Rhodesian, South Africa. (After A. S. Wood-
ward.)

xxi

ILLUSTRATIONS

G. Cro-Magnon. (After Verneau.)
In the female and young skulls the brow ridges are
less projecting or entirely lacking.

43. — Anthropoid and Human Skulls. Top View 69

A. Chimpanzee. (After Boule.)

B. Pithecanthropus. (After Dubois.)

C. Neanderthal (La Chapelle-aux-Saints). (After
Boule.)

D. Cro-Magnon. (After Boule.)

44. — Anthropoid and Human Skulls. Front View 70

(After Boule.)

A. Chimpanzee.

B. Neanderthal (La Chapelle-aux-Saints).

C. Modern European.

45. — Comparative Views of Sectioned Lower

Jaws ....... 71

A. Dryopithecus. (After Gregory and Hellman.)

B. Chimpanzee.

C. Piltdown. (After A. S. Woodward.)

D. Heidelberg. (After Schoetensack.)

E. Ehringsdorf. (After Virchow.)

F. Neanderthal (Le Moustier). (After Weinert.)

G. Cro-Magnon. (After Verneau.)

46. — The "Almost Human" Skull of Australopi-
thecus, a Young Fossil Anthropoid . facing 72
(After Dart.)

47. — Restoration of the Head of the Young

Australopithecus .... facing 73

(After a drawing by Forrestier made under the direc-
tion of Professor G. Elliot Smith.)

48. — Evolution of the Human Skull: Ten Struc-
tural Stages ...... 78

I. Lobe-finned fish, Devonian age (essentially
Rhizodopsis) . (After Traquair, Watson, Bryant.)

xxii

ILLUSTRATIONS

PAGE

II. Primitive amphibian {Palosogyrinut), Lower
Carboniferous. (After \V;itson.)

III. Primitive cotylosaurian reptile (Sri/mourin),
Permo-Curboniferous. (After BroiK, Williston, Watson.)

IV. Primitive theromorph reptile (MyctcrosauTus),
Permo-CiirboniferDus. (After Williston.)

V. Gorgonopsian reptile (Scymnognathiui), Permian.

(After Broom.)

VI. Primitive cynodont reptile {Ictidopsis), Tri-
assic. (After Broom, Haughton.)

VII. Primitive marsupial (Eodclphis), Upper Creta-
ceous. (After Matthew.)

VIII. Primitive primate (Notharctus), Eocene.
(After Gregory.)

IX. Anthropoid (female chimpanzee), Recent.

X. Man, Recent.

49. — Evolution of the Human Skull-roof . 79

Same series as in Fig. 48, except that in No. VII the
recent opossum instead of its fossil ancestor is used.

Abbreviations: na, nasal; fr, frontal, pa, parietal;
it, intertemporal; st, supratemporal; tab, tabular; dso,
dermosupraoccipital.

50. — Evolution of the Human Jawbones . . 80

Same series as in Fig. 49.

Abbreviations: pmx, premaxilla; mx, maxilla; dn,
dentary.

51. — Evolution of the Circumorbital Bones . 81

Same series as in Fig. 49.

Abbreviations: prf, prefrontal; la, lacrymal; ju,
jugal (malar); po, postorbital.

52. — Evolution of the Bones Behind the Jaws

(Temporomandibular Series) ... 82

Same series as in Fig. 49.

Abbreviations: sq, squamosal (squamous portion of
xxiii

ILLUSTRATIONS

FIGURE PAGE

temporal); quj, quadratojugal; sur, surangular; an,
angular; pospl, postsplenial; spl, splenial.

Figures 48-52 give excellent examples of " Williston's
law" of the progressive elimination of skull elements
in passing from fish to man.

53. — Evolution of the Under Side of the Skull 85

I. Lobe-finned fish (Eusthenopteron), Devonian.
(After Bryant, Watson.)

II. Primitive amphibian (Baphetes), Carboniferous.
(After Watson.)

III. Primitive cotylosaurian reptile (Seymouria),
Permo-Carboniferous. (After Watson.)

IV. Advanced cotylosaurian reptile (Captorhinus),
Permo-Carboniferous. (Original.)

V. Gorgonopsian reptile (Scymnognathus), Per-
mian. (After Watson.)

VI. Advanced mammal-like reptile (Cynognathus),
Triassic. (Mainly after Watson.)

VII. Marsupial mammal (Thylacinus), Recent.
(Original.)

VIII. Eocene lemuroid primate (Adapts). (After
Stehlin.)

IX. Anthropoid (female chimpanzee). (Original.)

X. Man (Australian aboriginal). (Original.)
Abbreviations: pmx, premaxilla; mx, maxilla; ju,

jugal; quj, quadratojugal; qu, quadrate; nar, internal
naris; pv, prevomer; pi, palatine; ectpt, ectopterygoid;
epipt, epipterygoid; pt, pterygoid; pas, parasphenoid ( =
vomer, v); bs, basisphenoid; bo, basioccipital; exo, exocci-
pital; ops, opisthotic; mst, mastoid portion of periotic;
bul, auditory bulla; sq, squamosal; alsp, alisphenoid.

54. — Anatomy of the Lancelet (Amphioxus) , the
Most Primitive Living Chordate (Pre-
vertebrate) Animal .... 92

(After Delage and Herouard.)

A. Entire animal, seen as a semi-transparent object.

B. Longitudinal section.

xxiv

[LLUSTRATIONS

55. — Larvae of Echinodbbms (A, B) and of the

"Acorn Worm" (lialanoylossus) . . . !K>

A. Aitriruluria, larva of a sea-cucumber.

B. Bipinnaria, larva of a starfish,

C. Tornaria, larva of Bcrtanoglossus.
(A, B, C, after Delage and Herouard.)

56. — Inner and Outer Mouth Pouches in Embryo

Vertebrates ...... 94

A. Larval lamprey, longitudinal section of head.
(After Minot.) Showing the nasal pit, hypophysis
and mouth cavity arising as infolds from the ectoderm
or outer cell-layer.

B. Embryo rabbit, longitudinal section of head.
(After Mihalcovics.)

57. — Attempted Restorations of the Mouth and
Gill Region of Two Cephalaspid Ostraco-
derms by stensio ..... 95

A. Horizontal section through the ventral part of
the head of Kiwraspis, showing the assumed position
of the gill-sacks.

The ducts (k. ebr.) leading from the gill-sacks are
preserved in the original fossils, also the ridges (i b s)
between the ducts, so that by comparison with the
anatomy of recent lampreys there is no substantial
doubt that the gill-sacks were placed as in the restora-
tion.

B. Underside of the head shield of Cephalaspis,
showing the probable position of the gill openings
(ebr. c ebr. c) and mouth (m).

58. — Swift-moving Ostracoderm (Pterolepis nitidus)

from the Silurian of Norway . . 96

(After Kiaer.)

59. — A Modern Descendant of the Ostracoderms 97

A. Adult lamprey. (After Jordan and Evermann.)

B. Longitudinal section of larval lamprey, enlarged
(After Goodrich.)

XXV

ILLUSTRATIONS

FIGURE PAGE

60. — Development of Teeth in Lamprey and

Shark ....... 99

(After Goodrich.)

Sections of developing tooth germs:

A. Lamprey.

B. Shark. First stage, showing tooth papilla
beneath basal layer of epithelium.

C. Shark. Second stage, showing secretion of
the enamel layer.

D. Shark. Advanced stage, showing lips of
shagreen denticles breaking through the epithelium.

61. — Evolution of the Jaw Muscles from Fish

to Man 103

I. Shark (Chlamydoselache) . (Data from Allis.)

II. Lobe-finned ganoid (Polypterus) . (After L. A.
Adams.)

III. Primitive amphibian (Eryops). Restoration.
(After L. A. Adams.)

IV. Primitive mammal-like reptile (Scymnognathus).
Restoration. (Skull mainly from Broom.)

V. Advanced mammal-like reptile (Cynognathus).
Restoration. (After L. A. Adams.)

VI. Primitive marsupial (Opossum). (After L. A.
Adams.)

VII. Primitive Eocene primate (Notharctus).
Restoration.

VIII. Chimpanzee.

IX. Modern man.

62. — Methods of Attachment of the Primary

Upper Jaw to the Under Side of the Skull 105

A. Hyostylic attachment (by means of the hyo-
mandibular cartilage), characteristic of shark. (After
Gegenbaur.)

B. Autostylic attachment (by means of an epi-
pterygoid process from the primary upper jaw). Car-

xxvi

ILLUSTRATIONS

FIGURE PAGE

tilaginous braincase and primary upper jaw of foetal
salamander. (After Gaupp.)

C. Skull of primitive fossil reptile (Diadectcx) from
the Pernio- Carboniferous of Texas.

In C the bony mask covering the temporal region is cut
through and a part of it removed to show the primary
upper jaw (comprising the palatine, pterygoid, epi-
pterygoid and quadrate bones) and their relations to the
braincase.

63. — Under Side of the Skull of (A) Devonian
Fossil Fish (Lobe-finned), Air-breathing
Crossopt (Eusthenopteron) and (B) Primi-
tive Fossil Amphibian (Baphetes). (A after
Bryant and Watson; B after Watson) . 108

The secondary upper jaws (premaxillae, maxillae)
are on the margins; the primary upper jaws (palato-
quadrates) are largely covered by tooth-bearing plates
of the primary palate.

64. — Right Half of the Lower Jaw of Lobe-
finned Fossil Fish (A, C), and Primitive
Fossil Amphibian (B, D), and Recent
Turtle Embryo (E) . . . .111

A. Mcgalichthys, outer side. (After Watson.)

B. Trimcrorhachis, outer side. (After Williston.)

C. Mcgalichthys, inner side. (After Watson.)

D. Trimcrorhachis, inner side. (After Williston.)

E. Recent turtle embryo, inner side. (After
Parker.)

Abbreviations of names of bones: ang, angular; art,
articular; cor, coronoids (I, II); dn, dentary; prcart,
prearticular; pospl, postsplenial; spl, splenial; surang,
surangular bone.

In the embryo turtle Meckel's cartilage is very
plainly seen on the inner side of the jaw, extending the
full length of the jaw. The rear end forms the articu-
lar bone of the adult.

These jaws are made mostly of the dermal sheathing
bones that in the embryo surround the primary carti-

xxvii

ILLUSTRATIONS

laginous jaw. The only part of the primary jaw present
in the adult is the articular bone.

65. — Early Embryonic Stages in the Develop-
ment op the Nose in Man . . .120

(After Keith.)

66. — Comparative Anatomy of the Human Palate 121

A. Recent shark, showing groove from nose to
front of mouth. (After Keith.)

B. Lizard, in which internal opening (choana)
from the nose opens in the forepart of the mouth cavity.
(After Plate, Allgem. Zool., Gustav Fischer.)

C. Lion pup with cleft palate, recalling in form the
palate of reptiles; showing internal opening of the nose
(indicated by the arrow-point) in the forepart of the
mouth cavity. In this abnormal specimen the second-
ary palate has failed to grow over to the mid-line.
(After Keith.)

D. Human embryo of the end of the sixth week,
showing the secondary palatal plates beginning to grow
in toward the mid-line and the "primitive choanse"
(arrow-point) still exposed in the forepart of the roof
of the pharnyx. (After Keith.)

67. — Longitudinal Section of Head in Young
Gorilla (A) and in Man (B), Showing
Relation of Tongue to Surrounding Parts 124

(After Klaatsch.)

68. — Longitudinal Section of Lower Jaw of

Monkey (A) and Man (B), Showing Attach-
ment of the Tongue Muscle to the Back
of the Jaw ...... 125

(After Robinson.)

In B the subdivision of the tongue muscle into strands
is over-emphasized in order to show how the upper
surface of the tongue could be thrown into different
contours by the contraction of different strands of the
genioglossus muscle.

xxviii

ILLUSTRATIONS

FIGURF PACK

('. Diagram of the genioglossus muscle in pro-
nouncing the sound "mi." (After Robinson.)

I). Diagram of the genioglossus muscle in pro-
nouncing the letter "T." (After Robinson.)

69. — Human Embryo of the Third Week . . 127

(From Eidmann, after His.)

Oblique front view of the head, showing mouth,
primary upper and lower jaw buds, gill arches and gill
slits.

(From Entw. d. Ztihne. . . , Hermann Meusser, Berlin.)

70. — Old Chimpanzee, Showing Extraordinary
Protrusion of the Lips in Anthropoids

facing 132
(From J. A. Allen, from a photograph by Herbert
Lang.)

71. — Three Stages in the Development of Human

Teeth 135

A. Future tooth-bearing skin still on the surface
of the mouth cavity. From a human embryo eleven
millimeters long.

B. Beginnings of the tooth-pouch. From a human
embryo sixteen millimeters long.

(A, B, from Eidmann, after Ahrens. Entw. d. Zahne. . .,
Hermann Meusser, Berlin.)

C. Beginnings of the pulp cavity. From a human
embryo thirty-two and one-half millimeters long.
(After Corning, Lehrb. d. Entw. des Menschen, J. F.
Bergmann.)

72. — Central Incisors of Gorilla and Man.

Enlarged . . . . . .137

A. Upper left incisor of young gorilla, palatal side,
showing small mammillae on incisal edge, basal swelling,
raised marginal rims and low lingual ridges.

B. Upper left incisor of fossil Neanderthal (Le
Moustier), showing mammillate incisal edge, basal
swelling and ridges. (After Weinert.)

xxix

ILLUSTRATIONS

FIGURE PAGE

C. Upper left incisor of fossil Neanderthal (Ehrings-
dorf), showing basal swelling and ridges. (After
Virchow.)

D. Upper left incisor of old Egyptian, showing
mammillate incisal edge, marginal rims and lingual
ridges. (After Hrdlicka.)

E. Lower right incisor of young gorilla, showing
mammillate incisal edge and faint lingual ridges.

F. Lower right incisor of Neanderthal (Le Moustier.)
(After Virchow.)

G. Lower right incisor (labial surface) of white boy,
showing mammillate incisal edge and labial ridges.
(From Hrdlicka, after Zuckerkandl.)

73. — The Three Types of Central Upper Incisors 139

(After J. Leon Williams.) Lower row, first type;
middle row, second type; upper row, third type.

74. — Palatal Arches of Anthropoids and Men . 140

A. Gibbon, female. (From Selenka, after Rose.)

B. Gorilla, male. (From Selenka, after Rose.)

C. Chimpanzee, female. (From Selenka, after Rose.)

D. Orang, female. (After Hrdlicka.)

E. Neanderthal man (Le Moustier). (From Weinert,
after Dieck.)

F. Modern white man, composite. (From Selenka,
after Rose.)

75. — Lower Front Premolars of Fossil Anthro-
poids and Man ..... 144

A. Fossil anthropoid, Dryopithecus fontani. (After
Gregory and Hellman.)

B. Fossil anthropoid, Dryopithecus cautleyi. (After
Gregory and Hellman.)

C. Fossil anthropoid, Sivapithecus himalayensis.
(After Pilgrim.)

D. Fossil Neanderthaloid (Ehringsdorf). (After
Hans Virchow.)

E. Homo sapiens. (After Selenka, from Rose.)

XXX

ILLUSTRATIONS

FIGUF.K PACS

76. — Milk Teeth of Man and Gorilla . 146

A. White child. (From Selenka, after Riise.)

B. Gorilla child. (From Sclcrika, after Itbse.)

77. — Ten Structural Stages in the Evolution
of the Human Dentition from Ascending
Geological Horizons . . .147

I. Substage a. Permo-Carboniferous. Myetero-
saurus, primitive theromorph reptile. (After \Yilliston.)
Substage b. Permian. Scylacosaurus, primitive mam-
mal-like reptile. (After Broom.) Substage c. Tri-
assic. Cynognathus, advanced mammal-like reptile.
(After Seeley.)

II. Triassic. Diademodon, advanced mammal-like
reptile. (Mainly after Seeley. Occlusion diagram by
author.)

III. Jurassic. Pantotherian (primitive pro-
placental). (Kindness of Dr. G. G. Simpson. Occlu-
sion diagram by Simpson.)

IV. Cretaceous. Pre-Trituberculate, Deltatheridium.
(From the original specimen. Occlusion diagram by
author.)

V. Lower Eocene. Primitive placental, Didel-
phodus. (From the original specimen. Occlusion dia-
gram by author.)

78. — Ten Structural Stages in the Evolution

of the Human Dentition (continued) . 1-48

VI. Middle Eocene. Primitive primate, Pronydi-
cebus. (After Grandidier. Occlusion diagram by
author.)

VII. Upper Eocene. Advanced tarsioid primate,
Microchosrus. (After Stehlin. Occlusion diagram by
author.)

VIII. Miocene. Primitive anthropoid primate,
Dryopithecus. (Upper molars mainly after Pilgrim;
lower molars from type of Dryopithecus cautleyi. Occlu-
sion diagram by author and Milo Hellman.)

XXXI

ILLUSTRATIONS

FIGURE PAGK

IX. Pleistocene. Primitive man, Mousterian.
(From stereoscopic photographs by J. H. McGregor
and from the published photographs by Weinert and
by Virchow (m3). Occlusion diagram by author.

X. Recent. Modern man, white. (From the original
specimen. Occlusion diagram by author.)

79. — The Dryopithecus Pattern in the Lower
Molar Teeth of Recent and Fossil
Anthropoids ...... 150

(After Gregory and Hellman.)

A. Fossil anthropoid (Dryopithecus fontani) . The
first lower molar shows the fovea anterior, the five
main cusps and the fovea posterior.

B. Fossil anthropoid (Dryopithecus cautleyi). The
third lower molar (at the left) shows a perfect Dryopi-
thecus pattern.

C. Fossil anthropoid (Dryopithecus frickce) . (Com-
pare Fig. 80 C.)

D. Recent orang-utan. The Dryopithecus pattern
is somewhat obscured by the secondary wrinkles of
the enamel.

E. Recent chimpanzee. The Dryopithecus pattern
in this particular specimen is slightly obscured by the
secondary wrinkles of the enamel. Cusp 6, a bud from
the hinder rim of the tooth is present in the second
lower molar. (Compare Fig. 80D.)

F. Recent gorilla. The teeth are elongated in a
fore-and-aft direction and the cusps are high and
nipple-like.

80. — Progressive Reduction and Loss of the
Dryopithecus Pattern in the Lower Molars
of Fossil and Recent Men. . . .151

(After Gregory and Hellman.)

A. Fossil Heidelberg man. Worn lower molar
crowns, showing clear traces of the Dryopithecus
pattern.

xxxii

ILLUSTRATIONS

FIGURK PACK

B. Fossil Ehringsdorf man. H< ■ t li the first and the-
second lower molar clearly show t lie- fovea anterior.

(Compare Fig. 7!)A.) The second lower molar shows
an early stage in tlie formation of the cruciform or
plus pattern.

C. Fossil Neanderthal man (Le Moustier), showing
modified Dryopithccus pattern. Cusp G, occasionally
found in the anthropoids, is present.

D. Recent Australian aboriginal. In the first
molar the Dryopithccus pattern is very evident; the
base of cusp 3 is in contact with the base of cusp 2;
cusp 6 is unusually large. In the second lower molar
the Dryopithccus pattern is changing into the plus
pattern.

E. Modern Hindu, showing Dryopithecus pattern
in the first lower molar, and plus pattern in the second.

F. Modern White, with modified Dryopithecus pat-
tern in the first lower molar, a complete plus pattern
in the four-cusped second molar, and a reduced third
lower molar.

81. — Dissection of Head of Shark, Seen from
Above, to Show Relations of Olfactory
Capsules to Brain, Eyes and Internal
Ears ....... 155

(Modified from Marshall and Hurst.)

82. — Jacobson's Organ in the Human Fostus . 159

A. Location of Jacobson's organ. The sound is
inserted into the opening of the organ. (After Corning.)

B. Frontal section of foetal human nose, showing
vestige of Jacobson's organ. (After Corning.)

(A, B, from Lehrb. d. Entw. des Menschcn, J. F.
Bergmann.)

83. — Longitudinal Section of the Skull in Man

and Chimpanzee . . . . .160

A. Adult female chimpanzee.

B. Man. (After Cunningham.)

xxxiii

ILLUSTRATIONS

84. — Broad, Forwardly-Directed Nose of Human

Fcetus (A), (after Kollmann) and Gorilla
Fcetus (B), (from Schultz, after Deniker) 161

85. — Connections of the Frontal, Ethmoid and

Sphenoid Sinuses with the Nasal Meati 163

(After Keith.)
86. — Development of the Face in Man . . 165

(From Eidmann, Entw. d. Zahne. . . , Hermann Meus-
ser, Berlin).

A. Embryo of about 9 millimeters length. (From
Eidmann, after His.)

B. Embryo of about 10.5 millimeters length. (From
Eidmann, after His.)

C. Embryo of about 11.3 millimeters length. (From
Eidmann, after Rabl.)

D. Embryo of about 15 millimeters length. (From
Eidmann, after Retzius.)

E. Embryo of about 18 millimeters length. (From
Eidmann, after Retzius.)

87. — Development of the Face in Man {continued) 166

A. Late foetal stage: embryo of 52 millimeters length.
(From Eidmann, after Retzius, Entw. d. Zahne. . . ,
Hermann Meusser, Berlin.)

B. Diagram of adult face, showing derivation of
different areas from the primary embryonic parts.
(Modified from Keith.)

88. — Nasal Profiles and Related Parts in Man 168

(After Schultz.)

A. Negro child.

B. Negro adult.

C. White child.

D. White adult.

Median or septal cartilage, black,
xxxiv

ILLUSTRATIONS

FIGURE PAGE

Shows the correlation of the extent of the septal
cartilage, the position of the front teeth and the form
of the nose.

89. — Extremes of Nose Form in Man . facing 170

A. Excessively wide short nose in African pygmy.
(From Martin, after Czekanowski.)

B. Excessively narrow high nose in a white man
(Tyrolcse). (From Martin, after Czekanowski.)

C. Excessively high nose bridge and long nose in
an Armenian. (After von Luschan.)

D. Excessively low nose bridge in South African
Bushman. (From Martin, after Schultz.)

(A, B, D, from Lekrb. d. Antkropol., Gustav Fischer.)

90. — Extremes in Face Form and Color . facing 172

A. Hottentot woman. (From Martin, after Poech,
Lehrb. d. Anthropol., Gustav Fischer.)

B. Nordic Swede. (From Lundborg and Runnstrom,
" The Swedish Nation," H. W. Tullberg.)

91. — The Beginnings of Eyes .... 175

A. Section of an ocellus, or eye spot, at the base of
a tentacle of a jellyfish (Catablema). (From Plate,
after Linko.)

B. Section of a "goblet eye" of a jellyfish (Sarsia).
(From Plate, after Linko.)

(A, B, from Allgem. Zool., Gustav Fischer.)

92. — Eye Capsules of Flatworm . . . 177

A. Location of eyes in flatworm {Planaria). (After
Parker and Haswell.)

B. Section of "goblet eye" of flatworm {Planaria).
(From Plate, after Hesse, Allgem. Zool., Gustav Fischer.)

93. — How the Eye Capsules of a Flatworm Serve

as Directional Organs .... 178

(From Plate, after Hesse, Allgem. Zool., Gustav
Fischer.)

XXXV

ILLUSTRATIONS

FIGURE PAGE

The arrows show the varying directions of the light.
In each case only a particular part of each retina is
stimulated, the rest being in shadow.

94. — Eye of Squid (Horizontal Median Section) 179

(From Plate, after Hensen, Allgem. Zool., Gustav
Fischer.)

95. — Development of the Eye in Cephalopod

Molluscs ...... 181

(After Plate, Allgem. Zool., Gustav Fischer.)

A. Early embryonic stage, showing the spherical
retina (represented in the Pearly Nautilus).

B. Snaring off of the eyeball and beginning of the
iris-folds and of a primary cornea.

C. Development of the lens on either side of the
primary cornea, or transparent septum.

D. Development of a secondary or outer cornea.

96. — Light Cells of Amphioxus .... 183

A. Forepart of a young Amphioxus, enlarged, show-
ing light cells (Becheraugen). (From Plate, after
Joseph, Allgem. Zool., Gustav Fischer.)

B. Cross-section of the spinal cord of Amphioxus,
showing the light cells, which are essentially like the
goblet eyes (Becheraugen) of invertebrates.

(From Plate, after Hesse, Allgem. Zool., Gustav
Fischer.)

97. — Evolution of the Vertebrate Eye as Con-
ceived by Studnicka .... 185

(From Plate, after Studnicka, Allgem. Zool., Gustav
Fischer.)

In still earlier stages it is supposed the vertebrate
eyes arose, as in invertebrates, through a down-
pocketing of the light cells (Fig. 91) on the surface of
the embryonic nerve furrow, or medullary fold. When
the fold closed over, as it does in the developing verte-
brate embryo, the future eye spots found themselves

xxxvi

ILLUSTRATIONS

FIGURE PACK

in the inner lining of 1 1 1 < - nerve tube or brain, with the

"rods" turned away from the light.

A. Stage in which the dorsal pair of "eyes" (pineal
and parapineal) are beginning to grow outward, as
well as the "paired" eyes.

B. Stage in which the eye stalks are forming.

C. Stage in which the lens and retina are beginning.
D-I. Subsequent stages in the formation of the

optic cup.

98. — The Right Eyeball and Its Six Muscles . 190

(From Plate, after Merkel and Kallins, Allgcm. Zool.,
Gustav Fischer.)

99. — The Right Eye of a Shark in Horizontal

Section ....... 192

(From Plate, after Franz, Allgem. Zool., Gustav
Fischer.)

100. — Diagram of Horizontal Section of the

Right Human Eye ..... 193

(Simplified from Plate, after Luciani, Allgcm. Zool.,
Gustav Fischer.)

101. — Tear-draining Canals of the Eye . . 194

(After Keith.)

102. — Front View of Infant and Young Skulls

of Anthropoids (A, B, C) and of Man (D) 197

A. Chimpanzee. (After Selenka.)

B. Gorilla. (After Selenka.)

C. Orang. (After Selenka.)

D. Human child. (After Martin, Lehrbd. Anthropol.,
Gustav Fischer.)

103. — The Human Organ of Hearing and

Balance ...... 203

(A and C, after Cunningham.)
A. Transverse section.

xxxvii

ILLUSTRATIONS

B. Diagram section of the cochlea, showing the
ascending and descending spiral duct and the cochlear
duct containing the organ of Corti or true organ of
hearing.

C. Greatly enlarged view of the cochlear duct,
showing the organ of Corti with its damper, hair cells
and hearing nerves.

104. — Series Showing the Membranous Labyrinth

or Inner Ear from Fish to Man . . 205

(After Retzius.) Right side; outer view.

A. Shark (Acanthias).

B. Ganoid fish (Lepidosteus) .

C. Primitive reptile (Hatteria).

D. Alligator.

E. Primitive mammal (Rabbit).

F. Man.

105. — Development of the Labyrinth or Inner

Ear of Man 206

(After Streeter.)

106. — Transverse Section of the Head in a
Frog, Showing the Relations of the
Middle Ear (there is no Outer Ear)
to the Inner Ear and of the Latter to
the Brain ...... 208

(After T. J. Parker and W. N. Parker.)

107. — Embryo Sturgeon, Showing Gill Clefts 209

(After W. K. Parker.)

108. — Human (A) and Macaque (B) Embryos,
Showing Origin of the External Ear
from Six Tubercles . . . .211

A. From Leche, after Selenka.

B. From Leche, after His, Keibel.

(A, B, from Der Mensch, Gustav Fischer.)
xxxviii

ILLUSTRATIONS

FIGURK PAGE

10!). -Ears ok Kootal Macaque (A) and of a Six

Months' Human Fcetus (B) . . 212

(From Plate, after Schwalbc, Alhjrm. Zoo!., (iustav
Fischer.)

110. — External Ears of Anthropoids and Men 213

(After Keith.)

A. Chimpanzee.

B. "Small chimpanzee type" (human).

C. "Chimpanzee type" (human).

D. Orang.

E. "Orang type" (human).

F. Gorilla.

G. Gibbon.

H. Lemuroid (Nycticebus).

111. — The Middle Ear of Man, Showing the

Auditory Ossicles . . . . .216

(After Cunningham.)

A. View of the left tympanum (drum membrane)
from the inner side. The ossicles are cut away except
the handle of the malleus, which is inserted into the
drum membrane.

B. The same, showing the three ossicles in place.

112. — Relations of the Parts of the Middle Ear

in an Extinct Mammal-like Reptile . 217

A. Side view of back part of lower jaw of Permo-
cynodon, a cynodont reptile from the Permian of Rus-
sia. (Mainly after Sushkin.)

The broken line indicates the position of the pouch
from the tubo-tympanal cavity as inferred by Watson
and Sushkin.

B. Rear view of the skull of Permocynodon, show-
ing the perforate stapes in position. (After Sushkin.)

The broken lines (added by the present author)
indicate his interpretation of the position of the middle-
ear chamber and of the tympanic membrane. The
existence of an extra columella, as in primitive rep-

ILLUSTRATIONS

tiles, is inferred from the presence of a facet on the
lower outer end of the quadrate.

113. — Origin of Auditory Ossicles . . . 218

A. Back part of the lower jaw of Cynognathus,
inner side. (Based chiefly on a cast of the type of
Cynognathus craternotus, combined with observations
and figures of Seeley and Watson.)

B. Fcetal mammal, Perameles. (Slightly modified
from R. W. Palmer.)

114. — Relations of Ossicles to Lower Jaw on

Fcetal Armadillo {Tatusia hybrida) . .221

(Composed from two figures by W. K. Parker.)

115. — The Reptilian Stage in the Development

of the Auditory Ossicles . . . 221

A. Lower jaw and attached auditory ossicles in
a fcetal hedgehog (Erinaceus). (After W. K. Parker.)

B. Lower jaw and attached auditory ossicles in a
human foetus of 43 millimeters length. (After
Macklin.)

116. — Young Chimpanzee, Showing Facial Expres-
sion ...... facing 222

(From a photograph by Herbert Lang.)

117. — Stockard's Linear and Lateral Growth

Types . . . . . . .232

(After Stockard.)

A. Infant.

B. "Linear" adult.

C. "Lateral" adult.

118. — Side View of Human Figure, to Indicate
the Anterior Tip and the General Direc-
tion of the Lateral Line . . . 234
(After Stockard.)

OUR FACE FROM FISH TO MAN

PART I

PORTRAIT GALLERY OF OUR ANCIENT
RELATIVES AND ANCESTORS

THE VALUE OF A FACE

For a billion years or more the ceaseless game
of life has been concerned with the capture and
utilization of energy for the benefit of the individual
and with the rhythmic storage and release of
energy for the reproduction of the race.

In all ages and in all branches of the animal
kingdom a face of some sort has been indispensable
to all but sessile animals, just because a face is
concerned primarily with:

The detection of desirable sources of energy;

The direction of the locomotor machinery to-
ward its goal;

The capture and preliminary preparation of the

energy -giving food.

OUR FACE FROM FISH TO MAN

Among the highest animals the face acts also as
a lure for the capture of a mate.

In nearly all the lower vertebrate animals, how-
ever, the most constant and dominating element
of the face is the gateway formed by the mouth
and arching jaws to the "primitive gut" or
digestive tract.

Around this architectural centerpiece the higher
facial designs gradually developed.

THE BEGINNINGS OF OUR FACE

Doubtless it is a far cry from the lowly Slipper
Animalcule, whose face consists only of a gash in
the side of its moccasin-like body, to the human
face divine, but among the thousands of known
living and fossil forms Nature has left us a number
of significant vestiges on the long pathway of
creation. Among the more primitive of the many-
celled animals the jellyfishes consist essentially of
a two-layered parachute-like sac, the inner layer
serving as a primitive gut, the outer layer chiefly
as an envelope. The mouth of the sac is greatly
puckered and the folds are produced into ten-
tacles, often endowed with nettle-like, stinging

threads. A diffuse nerve net extends everywhere

OUR ANCIENT RELATIVES

between the inner and the outer layer and is con-
centrated into a ring around the mouth. This
mouth is far from being homologous with our own.
It represents at most the "primitive streak" of
the early embryos of vertebrate animals. Never-

\m .mtk

..mt/t.

Fig. 1. The First Mouths.

Slipper animalcule (A) with gash-like mouth; Jellyfish (B), a two-layered

sac with primitive mouth. (Both after Parker and Haswell.)

For details, see p. xiii.

theless it was the starting-point for further de-
velopments.

The direct line of ascent toward the vertebrates
is not yet definitely known and we can only sur-
mise what the next few steps may have been.
The flatworms appear to represent highly devel-
oped descendants of the jellyfish group, which
had abandoned the drifting habits of their remote

OUR FACE FROM FISH TO MAN

ancestors and taken to living on the bottom in
shallow water. The simple pulsations of a bell-
shaped body, which were sufficient for jellyfishes,
were modified into writhings or contractions in
definite directions. Anyhow, radial symmetry
gave way to bilateral symmetry, the animals began
to progress in a fore-and-aft direction and the
sharp differentiation of heads and tails was in
full play.

The early evolution of a primitive head is also
well illustrated in certain flatworms (Fig. 2A), in
which the slender nerve threads are drawn together
to form the first rudiments of a brain and a very
simple type of eyes is attained. In the annelid
worms the head is further advanced, since the
mouth is now surrounded by various accessory
organs for the testing of the food, by horny jaws
moved by muscles for the capture of the food,
by elaborate eyes and by an extensive fusion of
nerve fibers into an incipient brain. The trilo-
bites and higher crustaceans (Fig. 2B) carry the
story onward, showing us how some of the jointed
projections from the sides of the body, which had
originally been developed as primitive legs, very
early began to serve the mouth by drawing, kick-

'"i /i

Fig. 2. Two Early Stages in the Evolution of a Head
(after Parker axd Haswell).

Flatworm (A), showing a head-and-tail differentiation, including the
beginnings of a brain and of eyes; Sand-flea (B), showing the interrelations
of eye, brain, mouth, leg-jaws and nerve cord.

For details see p. xiii.

OUR ANCIENT RELATIVES

ing or pushing the food within its reach, these
mouth-legs finally culminating in the various and
highly refined burglar tools so well wielded by the
swarming hosts of insects.

According to Professor Patten of Dartmouth,
the vertebrates were derived from the arachnid
stem — an ancient branch of the jointed animals
(arthropods), that is represented today by Limulus,
the "king-crab" (which is not a crab at all), and
by the arachnids (scorpions and spiders). But if
these disagreeable creatures are our remote rela-
tives, then the highly developed head which they
had acquired after so many millions of years of
struggle all had to be largely made over when the
vertebrate stage of organization was reached.
They had to sacrifice their elaborate leg-jaw
apparatus, their very mouths were stopped and
a new mouth and jaws were formed, their eyes
were turned upside down and inside out and
a new set of swimming organs had to be devel-
oped.

According to the more orthodox view, the verte-
brates from their earliest stages stood in wide
contrast to the crustaceans, arachnids and insects.
For while both groups comprise segmental animals,

OUR FACE FROM FISH TO MAN

moving in a fore-and-aft direction and building up
a complex head through the fusion of simple seg-
ments, yet the arthropods developed their jaws
out of jointed locomotor appendages while the
vertebrates utilized for this purpose the cartilagi-
nous bars of the first two gill pouches. According
to Patten's view the fossil ostracoderms (Fig. 4)
were more or less intermediate between these two
great groups; but the objections to this view are
formidable.

No matter from what group of invertebrates the
vertebrates may have sprung, their origin took
place many hundreds of millions of years after the
first synthesis of living matter from less complex
substances. When the first fishes took form the
seas already swarmed with thousands of species
of marine invertebrates, — protozoans, sponges, cor-
als, trilobites, crustaceans, brachiopods, arthro-
pods, molluscs, etc., and so far as the marine inver-
tebrates were concerned, all the major problems
of feeding, locomotion, sexual and asexual repro-
duction had been solved aeons ago. And when the
vertebrates started on their long career they too
had already solved all the same fundamental prob-
lems by rigorously sacrificing much of their old

ONE /CELLED

/ORGANISMS

Fig. 3. The Rise of the Vertebrates in Geologic Times.
Figures at left give estimated time in millions of years.

OUR FACE FROM FISH TO MAN

equipment and by profoundly changing what was
left of their original heritage. The earliest known
vertebrates (or more properly, chordates) are in-
dubitably far nearer to us in geologic time and in
the ground-plan of their whole organization than
they were to the first living creatures; even their
faces reveal them, as we shall presently see, as
early kinsfolk of ours; the real beginnings of our
facial type are either hidden in still unexplored
rocks of pre-Silurian ages or wiped out forever by
the destructive forces of erosion. From the view-
point of earth history as a whole, even the earliest
vertebrates of Silurian times (Fig. 4) rank among
the younger children of life, yet from the viewpoint
of mankind their antiquity is at first inconceivably
vast, since according to all recent geological in-
quiry, it must be reckoned in hundreds of millions
of years.

The recent monographic researches of Kiser and
especially of Stensio upon the amazingly well
preserved ostracoderms of the Silurian and Devo-
nian ages of Norway and of Spitzbergen have defi-
nitely shown that these curious forms are more or
less directly ancestral to the hagfishes and lam-
preys of the present day, which comparative

OUR ANCIENT RELATIVES

anatomists have long regarded as standing far
below the grade of the sharks in the seale of
vertebrate life. In some of these fossils the infil-

Fig. 4. Some of Our Earliest Known Kinsfolk.
Upper Silurian and Devonian Ostracoderms.

For details, see pp. xiii, xiv.

trated mud has made a natural cast of even the

principal nerves and blood vessels of the head, so

that Stensio has been able to show that they com-

OUR FACE FROM FISH TO MAN

pare very closely in the ground-plan of the anatomy
of their heads with the larval stages of the
lampreys.

In all these lowly creatures as well as in ourselves
the head is essentially the complex of sense organs,
brain and brain covering, mouth and throat, by
means of which the creature is directed to its food and
enabled to engulf it.

THE SHARK'S FACE AND OURS

The ancestors of the higher vertebrates did not
settle down and become specialized bottom-living
fishes but long maintained themselves in the fierce
competition of free-swimming, predaceous types.
Whatever the first steps leading toward the verte-
brate head may have been, the shark shows us
our own facial anatomy stripped of all elaborations
and reduced to simplest terms. Like Shy lock, the
shark might well plead that he has eyes, nose and
a mouth, affections, passions; accordingly we find
that in zoological classes all over the world the
humble dogfish affords an invaluable epitome and
ground-plan of human anatomy.

Men have been insulted by the implications of

this fact and still more by the statement that man

Fig. .3. The Face of the Most Primitive Living Shark (after Garman).
For details see p. xiv.

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£ 2

OUR FACE FROM FISH TO MAN

is far nearer in architectural plan to the shark
than the latter is to whatever invertebrates we
may choose to name as the starting-point of the
whole vertebrate tree of life; but such are the
secure judgments of comparative anatomy.

Much that might appear mysterious and in-
scrutable in the anatomy of the human face may
reasonably be explained as a heritage from far-off
shark-like ancestors, which human embryos also
recall. Let us therefore look a little more closely
into the construction and functioning of the face
of this human prototype.

Always remembering that the face is merely the
food-detecting and food-trapping mask in front of
the brain, we find in the shark's apparently simple
face a truly marvelous assemblage of instruments
of precision (Fig. 6). First among these food-
detecting devices rank the smelling organs, rosette-
like membranes exposed in the olfactory capsules
under the nostrils, capable of detecting chemically
the very minute quantities of blood or other animal
matter dissolved in sea water. These smelling
capsules lead by prominent nerve tracts to the
large forebrain, in which the smelling centers are

the dominant elements (Fig. 81).

OUR ANCIENT RELATIVES

In the brain these olfactory messages stimulate
the motor nerves controlling the eye muscles and
other nerves controlling the locomotor muscles, in
such a way that the shark turns and moves
toward the source of the odor.

The eyes of a shark are fundamentally similar
to those of a man but their marvelous intricacy
forbids an attempt to discuss them in this brief
space. Each eye is moved by six sets of eye
muscles (Fig. 6), which turn the pupil toward the
goal of movement.

As the food is reached and the stimulation of
smell, sight and other senses reaches its climax,
there is a convulsive expansion of the jaws, the
food is torn by the jagged teeth, the jaws snap shut
with the vicious force of a bear-trap, and the
intense pleasure of swallowing the precious life-
giving morsel is experienced.

Thoroughly equipped research laboratories could

profitably occupy the time for decades to come

with a study of what really happens when a shark

detects its food and rushes forward to engulf it,

for this apparently simple but in reality vastly

complex sequence holds many secrets of vital

importance to human beings.

OUR FACE FROM FISH TO MAN

However, the fact that even the true nature of
nerve currents is as yet very imperfectly known
does not prevent us from realizing the value of
even a homely face to all animals that navigate
the waters or move upon the land or in the
air.

Not the least important of the shark's detecting
and navigating instruments are the very numerous
"ampullae" that are so thickly scattered all over
the surface of the head. Each of these pits is con-
nected with a nerve tendril and thousands of
these nerves run together into larger tracts, which
finally run into the brain itself. Possibly these
ampullae detect vibrations of low frequency in
the water and in some way cooperate with the
olfactory nerves in giving stimuli proportional to
the nearness of the source.

Then there are the taste organs scattered over
the mouth cavity, all wired most carefully and
elaborately and connected with the appropriate
brain centers.

The so-called "internal ears" embedded in the

cartilage on either side of the hindbrain, consist

chiefly of the ingenious semi-circular canals (see

pages 202-6, Fig. 104), arranged like our own in

OUR ANCIENT RELATIVES

three planes and capable of analyzing any move-
ment of the body into three directional components.
These instruments of precision communicate
their findings to the brain and form essential
partners to the instruments carried by the face.
Capsules

Jaws

labia?
earff/cyep

-v-

Avoid aszc/V

/// '&rc/i 'PS

Fig. 7. Cartilaginous Skeleton op Head of Shark, Comprising

Braincase, Primary Upper and Lower Jaws and

Branchial Arches.

The scaffolding or skeleton of the face (Fig. 7)
consists of three principal parts: first, the carti-
laginous capsules (olfactory, optic, otic) that sup-
port the paired organs of smelling, sight and
balancing; second, the cartilaginous trough and
box that enclose the brain; third, the cartilaginous

upper and lower jaw-bars (palatoquadrate, Meck-

OUR FACE FROM FISH TO MAN

el's cartilage), with certain connecting bars (hyo-
mandibular, ceratohyal) that tie the jaws on to the
braincase.

These jaw cartilages resemble the bars of
cartilage (I-V) that form the supporting frame-
work for the gills.

.#^sc-

lev.m*sup

puadrate

Cartilage

; J / acfc/ucfor \\ ! / / /

fad car? mcmrftdittae ,-„«..,*■*: 'y '' ,

musc/e commctprmuscies

Fig. 8. Jaw Muscles of Shark, Showing the Essential Similarity

of the Jaw Muscles to the Constrictors of

the Branchial Arches.

For details, see p. xiv.

Even the jaw muscles appear to be modified

gill-arch muscles. The principal jaw muscles

(Fig. 8) are simply bands or sheets of muscle

wrapped around the angular bend where the upper

and lower jaw segments articulate with each other.

The lower jaw is pulled downward chiefly by a

backward pull of the horizontal muscles.

OUR ANCIENT RELATIVES

All these muscles, like those of the locomotor
apparatus, are composed of striped muscle fibers
and each little fiber is a sort of engine, deriving its
fuel from the chemical glycogen in the blood
and its explosive impulse from a tiny nerve
fiber.

Over the whole of this great complex is stretched
a tough but flexible envelope, the skin, which is
studded with minute teeth, or shagreen.

Around the jaw-bars the shagreen gives rise to
large teeth.

Thus in barest outline we have the elements of
the face and its connections with the braincase
in the shark. If we are fond of mysticism we will
say that in the cramped brain-box lives the shark
himself, who receives the multitudinous messages
from his detecting instruments and shapes his
actions accordingly. In this anthropocentric phil-
osophy a shark's face is highly expressive of the
shark's piratical and cruel character. If we wish
to be thoroughly behavioristic, on the other hand,
we will regard the shark's conduct as the automatic
resultant of the various stimuli received by his
sensorium, which were transmitted to the complex

apparatus in the central nervous system, the office

OUR FACE FROM FISH TO MAN

of which in turn is to play off one stimulus against
the other and to shape the motor responses into
profitable combinations. In this case the shark's
face is innocent of cruelty or piracy and is merely
an assemblage of coordinated instruments of pre-
cision packed into the forepart of a vessel of
appropriate streamline form.

At this place we do not have to discuss what
brought about this marvelous aggregation of
coordinated apparatus. All we need emphasize
is that in the face of a shark a man may behold,
as in a glass darkly, his own image.

Nevertheless a man should not flatter himself
that he is a direct descendant of some powerful
robber-baron such as the tiger-shark. Always in
earlier times we have been only the little stealers
of small fry and even when we attained the
mammalian grade we were still specializing in
capturing small living things.

THE MASK-FACE OF OUR GILLED ANCESTORS

A skull finds but little favor with the man in

the street and possibly it would not interest him

much to be told that every one of his twenty-eight

skull bones has been inherited in an unbroken

MM *&2

OUR ANCIENT RELATIVES

succession from the air-breathing fishes of pre-
Devonian times.

However, we wish to go even back of that and
are curious to know why animals ever acquired a
skull at all. The "basic patent" for the strength-
ening of all skeletal parts is the bone-cell, which
invades both the skin covering the head, where
it forms "derm bones," and the underlying carti-
lage or braincase; everywhere it deposits phos-
phate of lime and other salts, thereby greatly
stiffening the skin and strengthening the brain-box.

The skull of all vertebrates above the sharks is
a complex bony structure consisting of an outer
shell, or dermocranium, originally derived from
the many-layered skin, and an inner skull, or
endocranium, derived from the cartilaginous brain-
trough and its associated three pairs of capsules
for the nose, eyes and inner ears.

The same kind of cells surround the elastic

notochord or primitive axial rod, and deposit the

bony tissue along certain tracts between the tough

membranes that separate the muscle segments.

In this way rods called ribs are produced as well as

the bony arches above the notochord. All this

results in a strong framework, which supports the

OUR FACE FROM FISH TO MAN

powerful body muscles that drive the body through
the water.

The braincase is the thrust-block (Fig. 10) that
receives the forward push from the backbone and

Fig. 10. The Wedge-shaped Braincase of a Fish, Acting as a
Thrust-block or Fulcrum for the Backbone.

For details, see p. xiv.

the reaction from the water. The roofing bones
over the braincase and the keel bone (parasphenoid)
on the under side of the braincase together form
a long wedge which is thrust forward into the

water. To the sides of the skull are attached first,

Fir;. 11. The Facial Armor and Jaws of a Devonian Lobe-finned
Ganoid Fish (after Pander).

The skull seen from above. For details see p. xiv.

x g

OUR ANCIENT RELATIVES

the complex jaws, consisting of the primary or
originally cartilaginous upper and lower jaws plus
their bony dermal covering, and second, the sliding
bony covers of the gill chamber.

In the modern sharks the skeleton is stiffened
by calcium carbonate rather than by phosphate
of lime, the skin is stiffened chiefly by the shagreen
or little teeth on its surface and the skeleton as a
whole remains in a low stage of evolution.

On the other hand, in the ancient lobe-finned
ganoid fishes, which stand much nearer to the
direct line of human ascent than do the sharks,
phosphate of lime is deposited by true bone-cells
and the skull comprises a bony mask and a bony
braincase as described above.

The whole surface of the mask (Fig. 11) is cov-
ered by a thin enamel-like layer, smooth and
shining, called ganoine.

The jaws of the ancient ganoids, well covered
both on the inner and outer sides by an armor of
bony dermal plates, carried large sharp teeth with
deeply infolded or labyrinthine bases (Fig. 18A).

There is every reason to regard these mail-clad

robbers as lying not far off the main line of ascent.

The alligator-gar of the lower Mississippi system,

OUR FACE FROM FISH TO MAN

although belonging to another order of ganoid
fishes, bears a striking general resemblance to its
Devonian relatives.

Among these ancient ganoid fishes there are two
groups that have claims for the honor of standing
nearest to the main line of ascent. The first lot
were fierce, predatory, pike-like forms, which had
stout fan-shaped paddles, two pairs, corresponding
to the fore and hind limbs of land-living verte-
brates. To judge from the fact that they had
internal nares or nostrils as well as external ones,
these ancient lobe-finned ganoids already possessed
a lung in addition to gills and were therefore able
to breathe atmospheric air directly when the
streams and swamps in which they lived tem-
porarily became dry. Today this group of lobe-
finned or crossopterygian ganoids is represented,
if at all, only by two living genera of fishes: the
bichir {Polypterus) of the Nile and its elongate
relative Calamoichthys. In its mode of embryonic
development Polypterus shows resemblances both
to the lung-fishes and to the Amphibia.

The rival claimants for the honor of standing in
the human line of ascent were the true lung-fishes,

or Dipnoi. The several survivors of this group at

■H

« fe

OUR ANCIENT RELATIVES

the present time, including the famous lung-fish
(Neoceratodus) of Australia, all have very well-
developed and functional lungs in addition to gills.
Moreover, the embryonic development of the mod-
ern lung-fish, it has been shown, closely parallels
that of certain existing salamanders.

Nevertheless, all the fossil and recent fishes of
this dipnoan group had definitely and hopelessly
removed themselves from the main line of ascent,
since they had already either reduced or lost the
marginal bones of the upper jaw and had developed
peculiar and specialized fan-shaped cutting plates
on the roof of the mouth and on the inner side of
the lower jaw.

The earliest of the land-living or four-footed
vertebrates, on the contrary, retained the marginal
jaw bones and never developed the fan-shaped
cutting plates on the roof of the mouth.

To make a long story short, the real ancestors

of the higher vertebrates were probably neither

true dipnoans, nor any of the Devonian lobe-finned

ganoids, but were the still undiscovered common

ancestors of these rather closely related groups

living somewhere, perhaps in Lower Devonian or

Upper Silurian times.

OUR FACE FROM FISH TO MAN

The evidence of embryology and comparative
anatomy points unmistakably to the derivation of
the land-living vertebrates from air-breathing
fishes, with stout paired fore and hind paddles and
a complex skull of the general type described above.
The lobe-finned fishes as a whole appear to be

I^&^JS^

Fig. 14. Embryos of Modern Lobe-finned Fish (A) (after Bud-
gett) and Amphibian (B) (after S. F. Clarke).

For details, see p. xv.

near to the direct line of ascent, although each of

the known members of the group is probably too

late in time and too specialized in certain details of

skull structure to be the actual ancestor of the

land-living vertebrates.

In view of the mobility and fleshiness of the

human and other mammalian faces it may be

OUR ANCIENT RELATIVES

deemed surprising that one should seek to derive
the higher vertebrates from fishes whose whole
head and face were covered with a porcelain-like
armor; but in the following pages we shall follow
this amazing transformation step by step.

OUR ANCESTORS COME OUT OF THE WATER

Plant life is believed to have originated in the
sea in early Archeozoic times. As far back as
Devonian time it had succeeded after long ages of
struggle in adapting itself to terrestrial life and
there were great forests of low types of trees pre-
ceding the still greater swamps of the Coal age.
No remains of amphibians have hitherto been
found associated with Devonian plants, and the
transformation of air-breathing fishes into lowly
amphibians took place during the millions of years
in which the fossil record of vertebrate life is still
defective. But at the time of the formation of
the older coal beds of Great Britain there wTere
still surviving some very low types of amphibians
which retained more of the fish-like characters in
the skeleton than did any later forms known.

These highly interesting remains were imper-
fectly described by earlier authors but they have

OUR FACE FROM FISH TO MAN

been successfully restudied by Professor D. M. S.
Watson of University College, London, in the
light of his extensive knowledge of later fossil
amphibians. Under his keen scrutiny these oldest
known land vertebrates have yielded many facts
of far-reaching significance. He has shown that
in certain of these forms the shoulder-girdle was

Fig. 15. One of the Most Primitive Known Amphibians from

the Lower Carboniferous of England (Restoration

after Watson's Data).

For details, see p. xv.

still attached to the skull by a bony plate, as it is
in typical fishes, and that the bony plates of the
shoulder-girdle were still readily identifiable with
those of fishes, whereas in later types these plates
became highly modified.

The bony mask covering the face and braincase
of these oldest tetrapods x is of the greatest interest
in the present connection, for in it we find the
starting-point for everyone of the twenty-eight

1 A name often applied to the oldest four-footed land-living forms,
both amphibians and reptiles.

* am

Fig. 16. Skull of Oxe of the Oldest Known Amphibians
(Loromma allmani).

After Embleton and Atthey.
A. Upper surface. B. Under side.

OUR ANCIENT RELATIVES

bones of the human skull, together with many
other bony elements which were reduced and
gradually eliminated in the long procession of
forms from fish to man.

Before looking forward to man, let us look hack-
ward and see how the skulls of these earliest
explorers of the land compared with those of their
collateral ancestors, the air-breathing, lobe-finned
ganoids.

The greatest change is seen in the region of the
gill chamber, just behind the upper jaws. In the
fish this was covered by a beautifully jointed series
of bony plates, as perfectly articulated as any suit
of armor ever made by man. In the oldest
amphibians, however, these bony plates behind
the jaws have disappeared completely, leaving an
exposed area called the otic notch just behind the
upper jaw. This is the region of the middle ear
or sound-transmitting apparatus in modern amphi-
bians and apparently these ancient amphibians
had already acquired this new instrument of pre-
cision. In the lower jaw the bony plates covering
the under surface of the throat had also dis-
appeared. In the region above the nostrils the

mosaic of small bones found in the lobe-finned

OUR FACE FROM FISH TO MAN

fishes had been replaced by two large bones hence-
forth traceable directly to the nasal bones of man.
The several bony plates on the face surrounding
the eye had also been changed in proportions.

• marginal yu/ars

Fig. 17. Skulls of Lobe-finned Fish (A) and Early Amphibian

(B), Showing Loss of Opercular Series in the Latter

(A, after Traquair and Watson, B, after Watson).

In the primitive amphibians the space formerly covered by the
opercular region was covered by the tympanum or drum membrane.
For details, see p. xv.

^^frSr.

k — d

v^vvH^7

ilC J

Fig. 18A. Cross-section of Labyrinthodont Teeth. Lobe-finned
Devonian Fish (after Pander).
For details see p. xvi.

Fig. 18B. Primitive Amphibian of Permian Age (after
Embleton and Atthet).

OUR ANCIENT RELATIVES

On the other hand, many of the bony plates of
the skull roof were taken over with little change by
these oldest amphibians and the same is true of
the derm bones of the lower jaw. On the under
side of the skull (Fig- 53) the parasphenoid or keel
bone had grown backward so as to cover the base
of the braincase.

The teeth of the oldest amphibians were closely
similar to those of the lobe-finned ganoids, both in
general appearance and in microscopic structure.
The porcelain-like outer layer of the skin bones
covering the head of the lobe-finned fish had dis-
appeared, leaving a rough surface. Thus the face of
the oldest known amphibian, still consisting chiefly
of a bony mask, was not as different from that of
a lobe-finned fish as one might have expected.

Truly Nature's ways are not as man's ways.

After producing a beautiful mask-face of great

perfection and serviceableness, Nature started in

to reduce and simplify it and eventually to cover

up this mask with tender, sensitive flesh. From

now on, the story of the human skull is the story

of simplification and sacrifice of numbers, together

with the refinement and constant differentiation

of the elements that remained.

OUR FACE FROM FISH TO MAN

WHAT WE OWE TO THE EARLY REPTILES

The recent frogs, newts and salamanders, as
every high school student knows, go through a
fish-like or tadpole stage of development in the
water and resort to this ancestral medium at the
breeding season. The presence of fossilized gilled
young of amphibians in the Coal ages shows that
this water-breeding habit dates back very early
in geological time and is in harmony with the
origin of amphibians from swamp-living fishes. A
great and revolutionary advance occurred when
some daring amphibians succeeded in raising their
eggs entirely on dry land, for thus arose the rep-
tilian grade of organization and with it came the
possibility of all higher forms of life, including man.

With regard to the bony face, the most primitive
known reptile, Seymouria, has much in common
with the older amphibians. It still retains the otic
notch characteristic of the older forms and on its
skull roof it preserves the full complement of small
bony plates inherited from the amphibians and
lobe-finned fishes. Also its outer upper jaw bones
(maxillae) still retain their primitive slenderness.

In the same age which yielded Seymouria (the

OUR ANCIENT RELATIVES

Permian of Texas) lived another, decidedly higher
reptile, which had already acquired a significant
resemblance to some of the lower mammal-like

Fig. 19. Two Critical Stages in the Early
Evolution of the Skull.

A. Generalized reptile, retaining the full complement of amphibian

skull elements. (After data of Broili, Watson, Williston.)

B. Primitive theromorph reptile, with reduced number of skull
elements (after Williston). For details, see p. xvi.

OUR FACE FROM FISH TO MAN

reptiles of South Africa. This interesting form
{Mycterosaurus) was carnivorous, like other pro-
gressive reptiles, but had not become too far
specialized in this direction.

The most remarkable feature of its skull is a
circular hole on the side of the skull behind the eye.
This perforation in the bony mask of the temporal
region was the first foreshadowing of the "tem-
poral fossa" of the human skull.

As to the origin of this opening, studies on recent
and fossil skulls of many kinds of reptiles indicate
that the perforation arose through the progressive
thinning of the bone, due to the absorbent action
of the membranes surrounding the jaw muscle,
which was attached to its inner surface. Mean-
while, in resistance to the stresses induced by the
same muscle, the borders of the muscle area became
strengthened into bony bars or ridges.

The bony tract below the temporal opening dis-
tinctly prophesied the mammalian zygomatic arch,
the cheek bone of man.

Another progressive character of Mycterosaurus

is the vertical growth of the upper jaw bone

(maxilla), which up to that time had remained a

shallow bar in front of the eyes. In the lower

OUR ANCIENT RELATIVES

jaw the principal tooth-bearing bone, or dentary,
one on each side of the head, was relatively larger

smx

Fig. 20. Skulls of Earlier and Later Mammal-like
Reptiles from South Africa.

(Data from Broom, Watson, Houghton.)
For details, see p. xvi.

as compared with the other bony plates of the jaw

lying behind it, than it had been in earlier stages.

OUR FACE FROM FISH TO MAN

The next stage in the long ascent is found among
the extinct mammal-like reptiles of the Karroo
system of rocks in South Africa. Among these the
lowest (Fig. 20A) are nearly as reptilian as lizards,
while the highest (Fig. 20B) almost reach the
mammalian grade of organization. The bony mask
skull advances in various details toward the
mammalian type especially in the modelling of
the lower jaw, in the further development of a
temporal fossa, or muscle opening, and of a cheek
arch essentially of mammalian type.

THE ONE-PIECE JAW REPLACES THE COMPLEX TYPE

In later members of the series leading toward
the mammals the dentary bone increased in size
until it so far dominated over the elements behind
it that finally they were crowded out entirely and
the lower jaw of the adult thus came to consist
solely of the two dentary bones (one on each side)
connected at the front end, or symphysis. This
result was fraught with momentous consequences
for the further evolution of the bony face toward
the human and other mammalian types.

Meanwhile the dentary bone (Fig. 21) by reason

of its enlargement came eventually to press against

Fig. 21. Progressive Upgrowth of the Dentary Bone of the

Lower Jaw to Form a New Joint with the Skull.
A. Primitive mammal-like reptile; B. Advanced mammal-like reptile;

C. Primitive mammal.

For details, see p. xvi.

OUR FACE FROM FISH TO MAN

the very jaw muscles in which its upper end was
embedded. In other cases when a muscle mass
becomes subjected repeatedly to new pressures or
friction across its line of action the surrounding

/9I//PSA
(CAVITY OF MENISCUS)

\Vftiu*

EXTPTER

CONDYLE
OF JAW'

EXTPTER.
' MUSC.

GOA//ALE

Fig. 22. Origin of the Interarticular Disc, or Meniscus, Lying

Between the Lower Jaw and Its Socket in the

Skull. (After Gaupp.)

membranes give rise to a cushion or sac of con-
nective tissue filled with a clear liquid, which
serves to prevent the opposing surfaces from
grinding against each other. In an early embryo
(Fig. 22) of a primitive mammal (Perameles)
Professor E. Gaupp, the eminent comparative
anatomist of Fribourg, found that a part of one

OUR ANCIENT RELATIVES

of the jaw muscles (the external pterygoid) during
the course of its development passed between the
lower jaw and its socket in the skull and there gave
rise to the bursa or cushion (meniscus); this disc
in all typical mammals prevents the lower jaw
bone from grinding into its socket in the temporal
(squamosal) bone.

In the immediate ancestors of the mammals the
pressure of the dentary bone of the lower jaw
transmitted through the meniscus or interarticular
disc somehow resulted in the formation of a
corresponding socket in the squamosal (temporal)
bone of the skull.

Thus a new or mammalian joint was formed
between the dentary bone of the lower jaw and the
skull, while the old or reptilian joint, lying between
the quadrate bone of the upper jaw and the articular
bone of the lower jaw, was now greatly reduced in
size, continued in the service of the middle ear and
gave up its jaw-supporting function.

These great changes made possible all the new

lines of evolution of the teeth that the mammals

developed, which had never been possible for the

reptiles; with these improved dental equipments

the mammals soon overran the world, driving out

OUR FACE FROM FISH TO MAN

the reptiles and finally producing the primates,
which eventually gave rise to man.

Thus the human face owes the fundamental plan
of its upper and lower jaws to the mammal-like
reptiles and earliest mammals in which these im-
provements were first worked out.

OUR MASK-FACE BECOMES MOBILE

The origin of the mammals is one of the most
dramatic incidents in the whole story of human
transformation from fish to man. The central
problems set for the mammal-like reptiles were to
speed up all their vital processes and to maintain
them at a relatively high level; also to resist the
extreme changes of temperature of the harsh,
highly variable climates then prevalent, when
periods of glaciation alternated with tropical heat.
Means had to be found to insulate the body in
slowly conducting substances so as to defy the
cold ; on the other hand, to enable the body to cool
itself safely when over-heated. Reptiles have this
power to a limited degree but it is greatly enhanced
in the mammals. For this purpose many "basic
patents" had to be worked out in the heat-
conserving organs, in the circulation of body

OUR ANCIENT RELATIVES

fluids, in the breathing organs. The locomotor
machinery was vastly improved, the brain and
nervous system had to keep pace with the general
advance and a new and much less wasteful method
of reproduction had to be perfected.

Among the heat-regulating devices arising in
the mammals, we note the following: (a) the dia-
phragm, a complex structure arising from the
conjunction of various muscle layers of the neck
and abdomen; it acts as a bellows to draw fresh
air into the lungs and thus to increase the con-
sumption of oxygen; the liberation of heat is a
by-product; the glands in the skin multiplied and
gave rise to (b) sebaceous glands, pouring out a
wax-like substance that tends to keep the skin
soft and pliable; (c) sudoriparous or sweat glands,
lowering the body temperature by evaporation of
the exuded moisture.

Chief among the heat-retaining structures was

(d) the hair, which seems to have arisen from small

tactile outgrowths of the skin. These at first grew

out between the scales and later supplanted them.

We do not know exactly when this substitution

took place, as the skin of soft-skinned animals is

very rarely, if ever, fossilized, but the later mam-

OUR FACE FROM FISH TO MAN

mal-like reptiles of the Triassic age were already so
far advanced toward the mammalian grade that
it would not be surprising if the initial stages in

Fig. 23. Origin of the Facial Muscles of Man.

A. Primitive reptile with continuous bony mask covering skull. The
mask was covered with thick skin without muscles, as in the alligator.
(After Williston.) B. Modern reptile with an open or fenestrated skull
covered with thick, non-muscular skin. (From Fiirbringer, modified
from Ruge.) C. Primitive mammal in which the sphincter colli system
has grown forward over the face. D. Gorilla. E. Man. (C, D and E
after Ruge.) For details, see p. xvii.

OUR ANCIENT RELATIVES

the formation of hair had already begun in them.
At any rate, there is evidence that the bony mask
of the earlier reptiles was already beginning to
become leathery on its outer layer.

Even in the most primitive of living mammals
the hard bony mask of the face has already begun
to sink beneath the surface and a more or less
pliable skin has been developed. But the most
remarkable fact is that as the bony mask sank
beneath the surface the "facial muscles," so char-
acteristic of mammals alone among vertebrates,
came into being. Where did they come from?
In the reptiles the neck and throat are covered by
a thin wide band of muscle called the primitive
sphincter colli, which is activated by a branch of
the seventh cranial nerve. In mammals this
muscle, besides giving rise to the platysma muscle,
has grown forward between the bony mask and
the skin, along the sides and top of the face. As
it grew forward over the cheek it sent out various
subdivisions which either surrounded the eyes, or
covered the forehead and cheeks, or surrounded
the lips, or connected the lips with the cheeks, or
were attached to the ears. Whenever the muscle

mass sent forth a new branch it also sent into this

OUR FACE FROM FISH TO MAN

branch a twig from the main facial division of the
seventh nerve (Fig. 24). Thus what are called
the mimetic or facial muscles of mammals arose
by the forward migration and subdivision of a
muscle formerly covering the neck. For this doc-

Fig. 24. Diagram Showing the Chief Branches of
the Facial Nerve.

A. Gorilla. (After Huge.) B. Man. (After Weisse.)

trine the anatomists Ruge and Huber have

brought forward the most detailed and convincing

evidence. Thus while mammals were exposed to

cruel lacerations of the tender facial muscles, these

same muscles became of great use in moving the

lips, in closing the eyes, in moving the external

ears and finally, in the apes and man, as a means

of expressing emotion.

OUR ANCIENT RELATIVES

OUR LONG-SNOUTED ANCESTORS CROWD OUT THE
DINOSAURS

For many millions of years during the Age of
Reptiles the ancestral mammals enjoyed all the
advantages of a higher level of vital activity, a
higher body temperature, a better locomotor
system, larger brains and more economical repro-
ductive methods, which had made them far supe-
rior in grade to the group from which they sprang.
Nevertheless, in all parts of the world where fossils
have been found these advantages did not enable
the mammals to supplant immediately their swarm-
ing relatives the reptiles. On the contrary, the
reptilian class, which very early broke up into
many orders, including the turtles, lizards, snakes,
crocodilians, dinosaurs, birds, flying reptiles and
many others, for millions of years dominated the
earth, while both the mammals and the birds
remained small and inconspicuous. For all the
millions of years during which the dinosaurs ruled
the land, the fossil record of life as it is preserved
in Europe and North America so far reveals
extremely few mammalian remains, and these only
from very thin layers in widely separated parts

of the world.

OUR FACE FROM FISH TO MAN

Fig. 25. Successive Dominance of the Amphibians, Reptiles,
Mammals and Birds, Man.
Numerals at left stand for millions of years since beginning of period,
according to rate of " radium emanation " from uranium minerals,
based on Barrell's estimates.

Fig. 26. The Common Opossum, a " Living
Fossil" from the Age of Dinosaurs.

OUR ANCIENT RELATIVES

The known mammalian remains from these
great formations consist mostly of very fragmen-
tary jaws, with a few teeth in them, of tiny mam-
mals. Most of these mammals were no bigger
than mice, but in the closing stages of the Age
of Reptiles a few of them became as large as
beavers. Some of the mammals of the Age of
Reptiles in Europe and North America are believed
by certain authorities to be related to that most
archaic of mammals, the egg-laying Platypus of
Australia. Others seem to have been remotely
related to the existing marsupials or pouched
mammals, which today live chiefly in Australia.

The most primitive marsupial of today, how-
ever, is the common opossum of North America,
which is one of our oldest "living fossils." It is,
in fact, the little-changed descendant of a group of
mammals that lived in the latter part of the Age
of Reptiles. One of these ancestral opossums,
represented by a fossil jaw and parts of the skull
(Fig. 27), was found by Barnum Brown embedded
beneath a large dinosaur skull in Upper Cretaceous
rocks of Montana. This form, named Eodelphis
(dawn-opossum) by Dr. W. D. Matthew, has the

known jaw and skull parts so nearly like those of

OUR FACE FROM FISH TO MAN

its modern relative that we can actually fit the
contours of the fossil opossum skull fragments
into the skull of a recent opossum with very little
adjustment of the latter; so that we may safely
study the lowly 'possum as a representative and

-*" — '"^v "^

pa/ "*>^ S^_~Sg^-^^

Fig. 27. Skull Parts of Extinct Opossum, Superposed on
Outlines of Skull of Recent Opossum.

For details, see p. xvii.

descendant of the pouched mammals of the latter
part of the Age of Reptiles.

Even the modern opossum skull is at first sight
strangely similar to that of one of the mammal-
like reptiles of the far-off Triassic. It will easily
be seen from Fig. 28 that the opossum, like any
primitive mammal, has inherited the entire ground-
plan of its skull from its progressive reptilian

ancestor. Considering the great advance in gen-

OUR ANCIENT RELATIVES

eral grade of organization described above, it is
surprising that in the side view of the skull the

Fig. 28. Skulls of (A) Advanced Mammal-like Reptile and
(B) Modern Opossum.

For details, see p. xvii.

higher structural level of the opossum is indicated

chiefly by the few conspicuous features figured

below (Figs. 48-52). The jaw muscles of the

opossum now cover the parietal and part of the

OUR FACE FROM FISH TO MAN

frontal bones, whereas in the earliest stages they
lay beneath these bones.

Fig. 29. Long-snouted Relatives of Ours from
the Cretaceous of Mongolia. (Restorations.)

For details, see pp. xvii., xviii.

It has been explained above how this shift in

relations began, by the overlapping of the edges

OUR ANCIENT RELATIVES

of these bones by the jaw muscles, which finally
crept over and completely submerged the bone.
Thus by the time we reach the primitive mammal
stage of evolution almost the entire bony mask,
which had originated as the bony skin on the sur-
face, is now found covered by the facial and
jaw muscles.

The relatives of the opossum and other primitive
pouched mammals until several years ago were
the only mammals of Cretaceous times of which
anything definite was known as to their skull
structure. In 1924 and 1925, however, Roy C.
Andrews and his colleagues of the American
Museum of Natural History discovered in the
Cretaceous formation of Mongolia half a dozen
imperfectly preserved skulls which appear to
represent the forerunners of the higher or placen-
tal mammals (see also Fig. 77 iv below). These
little skulls, which have been described by the
present writer with the collaboration of Dr. G. G.
Simpson, bring strong evidence for the conclusions
of Huxley, Henry Fairfield Osborn, Max Weber,
W. D. Matthew and others that the remote
ancestors of the placental or higher mammals of

the Age of Mammals were small insectivorous

OUR FACE FROM FISH TO MAN

animals with sharp cusps and blades on their
tritubercular or triangular upper molar teeth.
In these little Cretaceous placentals the skull and
teeth were in many ways like those of certain
existing insectivorous mammals, such as the tenrec
of Madagascar.

All the evidence available from several sources
indicates that the remote ancestors of the line leading
to all the higher mammals, including man, were small
long-snouted mammals, of insectivorous habits and
not unlike some of the smaller opossums and insecti-
vores in the general appearance of the head.

BETTER FACES COME IN WITH LIFE IN THE
TREE-TOPS

Immediately upon the close of the Age of

Reptiles the mammals appear in certain regions in

North America and Europe in great numbers and

variety. Palaeontologists think it probable that

they came from Asia, possibly by way of the

Behring Straits land-bridge. In the Basal Eocene

or Paleocene rocks of New Mexico and a few other

places have been found thousands of fragments

of fossilized jaws and teeth and several incomplete

skeletons of mammals, ranging in size from mice

Fig. 30. The Pen-tailed Tree-shrew of Borneo.

A "living fossil" representing a little-modified survivor of the Cretaceous
ancestors of the Primates. (Based on photographs and data given by Le
Gros Clark.)

Fig. 31. The Spectral Tarsier of Borneo.

A highly specialized modern survivor of a diversified group of Primates that
lived in the Lower Eocene epoch over fifty million years ago. (Data from
specimen and photograph by H. C. Raven.)

OUR ANCIENT RELATIVES

to large badgers. These belong mostly to wholly
extinct families of placental mammals, usually
with very small brains and teeth variously adapted
for eating insects, flesh or vegetation.

In the Basal Eocene formation of Montana have
been found teeth and bits of jaws of mammals
that apparently were somewhat nearer to the line
of human ascent. One lot of teeth and jaws
appear to be related remotely to the existing tree-
shrews of the Indo-Malayan region. These little
animals in many ways approach the lowest of the
Primates, especially in the construction of the
skull and teeth.

The second lot of teeth from the Basal Eocene
of Montana are judged by Dr. Gidley of the U. S.
National Museum to be related distantly to the
existing tarsier of Borneo and the Philippine
Islands. These very curiously specialized noc-
turnal primates (Fig. 31) have enormous eyes,
large but simple brains, very short noses and very
long hind legs, upon which they hop about among
the trees. In brief, the tarsier family appears to
be one of those numerous groups that after attain-
ing a high level of general organization at a rela-
tively early period, start off on an extremely

OUR FACE FROM FISH TO MAN

specialized side line and thus remove themselves
from the direct line of ascent to higher forms.

Much more conservative and central in struc-
tural type are the fossil primates of the extinct
family Notharctidse from the Eocene of Wyoming
and New Mexico. The fossil skeletons of these
animals (Fig. 32) have grasping hands and feet
of the tree-living type preserved in the modern
lemurs of Madagascar. The same is true of the
feet of the extinct lemuroid primates of the family
Adapidse from the Eocene of Europe.

Comparative anatomical and palwontological evi-
dence unite to support the view that all the primates
first went through an arboreal stage, some of them
afterward coming down to the ground and carrying
with them many of the structural ''patents'9 acquired
during their long schooling in the trees.

The hind foot of all known fossil and recent
primates below man is of the tree-grasping type
with a divergent great toe and there is no substan-
tial doubt, after the exhaustive critical discussions
of this subject by Gregory (1916, 1921, 1927),
Miller (1920), Keith (1923), Schultz (1924), Mor-
ton (1924, 1927) and others, that the whole order

was from its first appearance primarily tree-living

Fig. 32. Skeleton of a Primitive Fossil Primate from
the Eocene of Wyoming (after Gregory).

For details see p. xviii.

OUR ANCIENT RELATIVES

in habit and that the foot of man has been derived
from a grasping type with a divergent great toe.

Tree-living, possibly combined with nocturnal
habits, favored the evolution of keen sight, and in
the oldest known skulls of primates, from the

Fig. 33. Skull of a Primitive Primate of the Eocene Epoch
(after Gregory).

For details, see p. xviii.

Eocene perhaps fifty million years ago, we find
the eye orbits already larger and better defined
than those of contemporary terrestrial mammals.
The skull of one of the best known members of
this group is drawn in Fig. 33, from fossil speci-
mens in the American Museum of Natural History.
In this form the chief advance beyond the primitive
mammalian type (Fig. 27) is seen in the increase

in the size of the eyes and the beginning of the

OUR FACE FROM FISH TO MAN

shifting of the eyes toward the front of the head.
The muzzle, or olfactory chamber, is not yet
reduced.

The still surviving primates afford a remarkably
well graded series of faces, from the fox-like face
of Lemur (Fig. 34A) to the quaint old-man-like
faces of some of the Old World monkeys (Fig. 34C).
In the lower forms (Lemur, etc.) a rhinarium, or
moist patch, is present at the tip of the long snout,
the opposite lips are separated by a notch in the
mid-line and lack the mobility seen in the higher
forms. In the latter, with the shortening of the
muzzle, the rhinarium gives place to a true nose,
the mucous-secreting skin being limited to the
inner side of the nostrils and the nose eventually
growing out between the nostrils. Meanwhile the
opposite upper lips have become more broadly
joined at the mid-line and finally the lips become
highly protrusile through the constricting action
of the strong orbicularis oris muscle.

In the New World, or platyrrhine, monkeys
(Fig. 34B), which appear to represent an independ-
ent offshoot from some primitive tarsioid stock,
the nostrils are widely separated, opening out-
wardly on each side of the broad median part of

.* i •'.

Fig. 34. Ascending Grades of Faces in the Lower
Primates (after Elliot).

A. Lemur; B. South American monkey; C. Old World monkey.

For details see p. xviii.

OUR ANCIENT RELATIVES

the nose. In the Old World, or catarrhine series
(including the monkeys, apes and man), the nos-
trils are drawn downward and inward toward the
mid-line, so that they tend to make a V, with the
tip pointing downward. The subsequent history
of the nose and lips will be considered below
(pages 129, 153).

The external ears of the lower primates also
show many gradations from a more ordinary
mammalian type (see below, pages 211-213) to the
man-like ears of the chimpanzee and gorilla.

The habit of living either in trees or in a forested
region, in so far as it afforded opportunities for
securing insects, buds, tender shoots and fruits,
made possible the various lines of evolution of the
teeth which we observe in studying the fossil and
recent primates. In the earliest forms the denti-
tion as a whole retains clearer traces of an earlier
insectivorous stage, with triangular sharp-cusped
upper molar teeth. In the anthropoid the habit
of eating tender shoots and buds is reflected in the
molar teeth, which now have broad crowns with
low-ridged cusps. The human dentition, while
secondarily adapted for a more varied diet, still

bears many indubitable traces of its derivation

OUR FACE FROM FISH TO MAN

from a primitive anthropoid stage like that of the
fossil apes Dryopiihecus and Sivapithecus.

Fig. 35. Top View of the Skull in Representatives of Six

Families of Primates, Showing the More Forward Direction

of the Orbits in the Higher Forms.

A. Fossil lemuroid; B. African lemur; C. Tarsier; D. Marmoset;
E. Gibbon; F. Chimpanzee.
For details, see pp. xviii, xix.

In some of the existing lemurs of Madagascar
that retain the fox-like muzzle with its large smell-
ing chamber, the eyes are less enlarged and look

Fig. 36. Side View of Skulls of Primates, Showing Progressive

Shortening of the Muzzle, Downward Bending of the

Face Below the Eyes and Forward Growth of the Chin.

A. Eocene lemuroid; B. Old World monkey; C. Female chimpanzee,
D. Man. (B and C after Elliot.) For details, see p. xix.

OUR FACE FROM FISH TO MAN

partly outward as well as forward. But in all the
more advanced lemuroids the eyes are larger, with
more or less protruding orbits which tend to shift
forward, finally restricting greatly the interorbital
space and nasal chamber. This process culmi-
nates in the nocturnal galagos and in Tarsius
(Fig. 31), in which the eyes are enormous and the
eyes themselves are directed forward, although
the orbits are directed obliquely outward.

In none of the lower primates, however, are the
bony orbits directed fully forward and in none of
them are the upper jaws prolonged downward
beneath the eyes, as they are in the monkeys,
apes and man.

The families of man, apes, monkeys, tarsioids,
lemurs and tree-shrews are exceedingly rare as
fossils except in a few localities and geologic
horizons and the known remains usually consist
chiefly of broken jaws with a few teeth. Never-
theless these fossils are of high value when studied
together with the manifold families, genera and
species of primates still living. In a series of
publications beginning in 1910 I have shown how
fully these recent and fossil forms, from tree-
shrews to man, reveal the structural stages in the

Fig. 37. Epitome of the Fos-
sil History of Human and
Prehuman Primates.
(1927.)

I MAN

ANTHRO-
il POIDS

IfC-rPiMK

PR0T0-

ANTHROPOIDS

LOWER
PRIMATES

TREESHREVv«

55-faO

A. Tree-shrews (after Simpson;
back part of jaw from modern
tree-shrew); B. Primitive lemu-
roid (after Matthew); C. Proto-

IICfPMMi

BCfPIMi

BttPim

anthropoid; D. Proto-anthropoid
(C and D after photograph by
McGregor) ; E. Man-like anthro-
poid (after Pilgrim); F. Dawn-
man; G. Primitive man (after
Schoetensack) ; H. Modern man
(after Gregory).

21 . ♦. ..3.

The figures on the rignt give tne estimated duration of time in millions
of years since the beginning of each epoch. For details, see pp. xix, xx.

a
w

w
«
Ph

iZi

l-H

RECENT
PLEISIOCElNE

A A

I MAN

ANTHRO-
POIDS

PROTO-

ANTHROPOIOS

LOWER
PRIMATES"

TREESHREWS

Molars of: A. Primitive
tree-shrew; B. Primitive tree-
shrew; C. Primitive lemuroid
(after Matthew); D. Primi-
tive lemuroid (after Mat-
thew); E. Proto-anthropoid;
F. Proto-anthropoid (E and
F from stereoscopic photo-
graphs by McGregor); G.

Proto-anthropoid; H. An-
thropoid; I. Anthropoid; J.
Dawn-man; K. Neanderthal
man; L. Neanderthal man
(H, I, J, K, L, from stereo-
scopic photographs by Mc-
Gregor); M. Modern man;
N. Modern man.

For details, see pp. xx, xxi.
62

OUR ANCIENT RELATIVES

evolution of the teeth, jaws, braincase, middle
and inner ear, vertebral column, pelvis, hands
and feet.

Meanwhile Elliot Smith, Tilney, Hunter, Le Gros
Clark and others have shown how the existing
tree-shrews, lemurs, monkeys, apes and man pre-
sent a progressive series in the evolution of the
brain as a whole and of the various nuclei and
centers controlling bodily functions and be-
havior.

Sir Arthur Keith and others have also traced
step by step the structural adjustments in the
diaphragm, abdomen and pelvic floor, as the
originally horizontal body assumes a sitting po-
sition or moves erect as in the gibbon and
man.

It is remarkable how completely the results of
the students of the nervous system and of the
anatomy of the viscera accord with studies on the
evolution of the teeth, skull, limbs, etc., and on
the classification and fossil history of the families
and genera of Primates.

Taken together, these results afford cumulative

evidence for the conclusions that man still bears in

his whole organization an indelible stamp of the

OUR FACE FROM FISH TO MAN

tree-living habits of his remote primate ancestors
and that these tree-living adaptations were overlaid
by a later but very extended series of adaptations
for bipedal running on the ground.

THE ALMOST HUMAN FACE APPEARS

Doubtless many factors conditioned the pro-
gressive enlargement and differentiation of the
brain, which is so marked a characteristic of the
whole Primate order, but perhaps the leading
factor was the correlated use of eyes and hands and
at first, feet, not only in locomotion but in the
seizure and manipulation of food. And no doubt
the habit of sitting upright also tended to free
the hands for the examination of nearby objects,
while the habit of climbing in an erect posture, as
in the gibbon, finally gave rise to the almost
human face of the anthropoid apes, as will pres-
ently be shown.

We do not yet know the exact time and place

in which certain advanced primates began to take

on specifically human characters, although there

is much evidence at hand indicating that the time

was not much earlier than the Lower Miocene,

and the place somewhere within the known area

Fig. 39. One of Our Nearest Living Relatives. Female
Chimpanzee and Young.

(From " Almost Human," by R. M. Yerkes. Courtesy of the author
and The Century Company).

For details see p. xxi.

Fig. 40. Male and Female Chimpanzees.
(After J. A. Allen, from photographs by Herbert Lang.)

OUR ANCIENT RELATIVES

of the anthropoid stock at that time, which ranged
from India to Spain. But Darwin's conclusion
that mankind represents a peculiar and specialized
offshoot from the anthropomorphous subgroup of
Old World primates, after three-quarters of a
century of anatomical and palseontological re-
search, is backed by a mountain of evidence.

The female chimpanzee in the side view of the
skull stands nearer in resemblance to man than it
does to the primitive Eocene primate Notharctus.
The chimpanzee in fact has acquired all the
"basic patents" in skull architecture which were
prerequisite for the final development of the
human skull.

The most eminent students of the brains of

animals and men conclude that partly as a result

of the necessity for keen sight in actively climbing

animals, the eyes in primates (Fig. 35) moved

around from the sides of the face, where they are

in the lower vertebrates, and were brought to the

front, where in the anthropoid apes they finally

acquired bicon jugate movements and stereoscopic

vision. In the anthropoid apes, moreover, the

sense of smell no longer dominates the brain

system as it did in lower vertebrates, but its reign

OUR FACE FROM FISH TO MAN

is usurped by the sense of sight. Concomitantly,
the brain of the chimpanzee has increased greatly
so that the braincase is distinctly subhuman in
appearance. The erect position assumed by apes
that climb so much by means of their arms as
do the anthropoids has conditioned the bending
downward of the face upon the braincase (Fig.
36).

Everyone recognizes in the chimpanzee (Fig. 40)
a gross caricature of the human face, in which
the mouth and lips are absurdly large and the nose
flat with little or no bridge. But from the anthro-
poid viewpoint the human face may well appear
equally grotesque, with its weak little mouth,
exposed lips and unpleasantly protruding nose.
Possibly the common ancestor of man and apes
would be shocked by each of his descendants. But
allowing for much divergent evolution in the end
forms, what makes men and anthropoids so much
more like each other in fundamental features of
the face than either is to the oldest forerunners of
the entire order, long antedating their nearer
common ancestor? First, let us set down in
parallel columns a few of these resemblances

and differences.

Fig. 41. Left Lower Cheek Teeth of Fossil Anthropoid (B) from
India and Fossil Primitive Man (A) from Piltdown, England.

(A, from photograph by J. H. McGregor; B, after Gregory and Hellman).

The lower molars of the Piltdown jaw, although much ground down by
wear, show the pure " Dryopithecus pattern" characteristic of recent and fossil
apes.

For details see p. xxi.

OUR ANCIENT RELATIVES

EARLIER PRIMATES

(Cf. Figs. 33, 34A,
35A, 36A)

ANTHROPOIDS AND
PRIMITIVE MAN

(Cf. Figs. 35 E, F,
42, 43, 44)

Muzzle and snout

Long, pointed, extend-
ed chiefly forward

Short, wide, extended
chiefly downward

Mouth

Narrow, elongate

Wide, short

Tongue

Narrow

Broad

Lips

Not protrusile

Strongly protrusile

Number of premolars,
upper

Four

Two

Number of premolars,
lower

Four

Two

Form of first and sec-
ond upper molars

Triangular, three
main cusps

Quadrangular, four
main cusps

Cusps of lower molars

Sharp

Low, blunt

Lower jaw

Long, slender

Short, deep

Opposite halves of
lower jaw

Separate

Fused in front

Eyes

Look outward and
forward

Look forward, binocu-
lar, biconjugate

Bony partition behind
eye orbits

Barely begun

Complete

Premaxilla and max-
illa

Separate

Fused in adult

Occipital condyles

On rear of brain base

More on under side
of brain base

This comparison could be greatly extended by

the inclusion of technical anatomical details, but

is sufficient to indicate the main features of the

bony face in which man and the anthropoids have

advanced beyond the primitive primates. In the

earliest primates the characters mentioned above

are already adapted to a diet of insects and vege-

OUR FACE FROM FISH TO MAN

tation and to a horizontal position of the vertebral
column; the anthropoids, on the other hand, are
chiefly frugivorous and their vertebral column is
more or less erect.

Fig. 42. Fossil Anthropoid and Human Skulls.

A. Australopithecus, a young extinct anthropoid (after Dart) ;

B. Eoanthropus (after A. S. Woodward and J. H. McGregor);

C. Pithecanthropus erectus (after Dubois); D. Neanderthal (after
Boule); E. Talgai (after S. A. Smith); F. Rhodesian (after A. S.
Woodward); G. Cro-Magnon (after Verneau).

In the female and young skulls the brow ridges are less projecting or
entirely lacking. For details, see pp. xxi, xxii.

OUR ANCIENT RELATIVES

The close anatomical relationship of man to the
anthropoids, together with the fundamental iden-

Fig. 43. Anthropoid and Human Skulls. Top View.

A. Chimpanzee (after Boule); B. Pithecanthropus (after Dubois);
C. Neanderthal (after Boule); D. Cro-Magnon (after Boule).

tity in the molar patterns (Fig. 41) of the most
ancient fossil men to those of still older anthro-
poids, indicates that man has been derived from

frugivorous pro-anthropoids and that after man

OUR FACE FROM FISH TO MAN

left or had been driven forth from the ancient
forests, his omnivorous-carnivorous habits were
developed during the age-long and bitter struggle
for life on the plains. Thus the gentle pro-
anthropoids, quiet feeders on the abundant fruits
of the forest, introduced a long period of peace-
ful development in the strenuous upward struggle.

Fig. 44, Anthropoid and Human Skulls (after Boule).
A. Chimpanzee; B. Neanderthal; C. Modern European.

This peace was rudely broken when from some
zoological Garden of Eden, that is, from the center
of post-anthropoid evolution, the ancestral horde
of savage pro-hominids were turned out on the
plains to devastate the world.

AT LAST THE PERFECT FACE

As yet there is an immense hiatus in the palseon-

tological history of man, covering at least several

million years in the Pliocene epoch. All known

'II
II

'^y^\

1
1
;

W-- " ^ip
0 =_^2

Fig. 45. Comparative Views of Sectioned Lower Jaws.

A. Dryopithecus (after Gregory and Hellman); B. Chimpanzee;
C. Piltdown (after A. S. Woodward); D. Heidelberg (after Schoeten-
sack) ; E. Ehringsdorf (after Virchow) ; F. Neanderthal (after Weinert) ;
G. Cro-Magnon (after Verneau).

OUR FACE FROM FISH TO MAN

early human fossils are unquestionably human in
one way or another — even including the famous
Pithecanthropus, which zealous anti-evolutionists
stoutly refuse to admit to the human family. But
it is also noteworthy that each of these earliest
human relics is ape-like in a different way. The
Piltdown lower jaw (Fig. 41) and teeth are extra-
ordinarily ape-like; the Pithecanthropus skull (Fig.
42C) is ape-like both in its projecting brow ridges
and in certain features of the occiput, while the
braincast, according to all expert analysis, is far
inferior in certain respects to that of Homo sapiens;
the Heidelberg jaw (Fig. 45D) has a receding chin
and the Mousterian skull has many primitive ape-
like details in the teeth (Fig. 45F) that are usually
lost in Homo sapiens. The Rhodesian skull (Fig.
42F) shows remarkably gorilla-like details of the
bony lower border of the nose, indicating a very
low form of nasal cartilages and nostrils ; the Talgai
(Australia) skull is a proto-Australoid type with
extreme prognathism (Fig. 42E). The Australopi-
thecus skull (Fig. 42A) is that of a young anthro-
poid with an exceptionally well developed brain
(Dart, Sollas, Broom). While it may be nearer

to the chimpanzee than to man, its brain, skull

Fig. 46. The "Almost Human" Skull of Australopithecus, a Young
Fossil Anthropoid (after Dart).

Fig. 47. Restoration of the Head of the Young
Australopithecus.

(After a drawing by Forrestier made under the direction
of Elliot Smith.)

OUR ANCIENT RELATIVES

and teeth tend to bridge the gap between the high-
est apes and the lowest men.

Such were the last fleeting souvenirs of the pre-
human stage, surviving millions of years after the
first separation of the human and great ape fam-
ilies. They represent various degrees of approxi-
mation toward the modernized type of face, from
the almost ape-like lower jaw of Piltdown to the
highbred old man of Cro-Magnon (Fig. 42G).
Thus the scant evidence suggests that even in
Lower Pleistocene times there were already several
different types of mankind, some (such as Pilt-
down) more progressive or less ape-like in the
shape of the forehead, while more conservative in
the form of the dentition and jaw, others (Pithe-
canthropus) with a lower form of forehead and not
improbably a more progressive form of jaw.
Whether these represent individual, racial or
specific difference is not fully demonstrated; in any
case they suggest that within the family of man-
kind there was a remarkably wide range of varia-
bility in facial characters, as there still is.

The profound agreement between mankind and

the anthropoid group in anatomical characteristics

and in physiological reactions and to a certain

OUR FACE FROM FISH TO MAN

extent in basic mental traits (Yerkes, Koehler) all
sufficiently establish the fact that at one time the
human and anthropoid groups converged back-
ward to a common source. It is also the plain
teaching of comparative anatomy that the modern-
ized white human face with its small mouth, weak
jaws, reduced dentition, projecting chin, delicate
projecting nose and pale skin, has changed far
more from the primitive man-anthropoid starting-
point than has the face of a young chimpanzee,
with huge mouth, strong teeth, receding chin and
flat nose. Professor Osborn holds that the separa-
tion of man and apes from the primitive anthro-
poid stock began as far back as the Lower Oligo-
cene epoch, possibly some thirty -five million years
ago, while the present writer is inclined to date
this event from the next higher epoch, namely
the Lower Miocene, possibly nineteen million
years ago. l

Whichever date, if either, may eventually prove
to be the true one, the fact remains that in its
present form the modernized human face is sui

1 These figures are according to the tentative estimates of the geo-
logical epochs worked out by Barrell by the "radium emanation"
method, based on the rate of disintegration of radioactive ores from
different geological horizons.

OUR ANCIENT RELATIVES

generis, just as the face of any other species of
mammal is unique in its specific attributes. But
there are thousands of good scientific reasons for
accepting as a fact the evolution of man from
lower mammals, there is a convincing chain of
known forms in the long series from fish to man;
and even in civilized man the human face is most
obviously related rather closely to that of the
anthropoids; therefore only the most confirmed
mystic by preference will insist that the evolution
of the human face is a "mystery." It is true that
every event of the kind abounds in mystery, since
no matter how fully we can describe by what
stages it happens, we uncover infinitely ramifying
problems whenever we attempt to isolate the
causal factors.

Undoubtedly when primitive man left the forests
and came out on the plains to live by hunting there
was a change in food, a change from a frugivorous
to at least a partly carnivorous diet, there was a
change of locomotion from erect tree-climbing
(brachiation) to bipedal running on the plains;
speech arose and the brain grew so large that it
grew faster than the face; the period of individual

growth and development was greatly extended; all

OUR FACE FROM FISH TO MAN

the system of the ductless glands which has so
profound an effect upon growth and development
was affected in innumerable ways and differently
in different individuals and races. Thus we begin
to sense the complexity of the factors influencing
the emergence of the typical human face from a
primitive anthropoid type.

Whatever the causes may have been, the evi-
dence indicates that, starting with a face not dis-
similar to that of an immature female chimpanzee
(Fig. 40B), the forehead rapidly became larger,
the incisor teeth became less inclined, more vertical
and smaller in size, the canine teeth diminished
in size and in such a way that the tip of the lower
one finally passed behind the front edge of the
upper canine; the premolars and molars also
decreased in fore and aft diameter. In addition
to the reduction and backward displacement of
the teeth there was a positive outgrowth of the
bony chin, which possibly on account of the early
development of the tongue could not retreat fur-
ther backward. The later stages of this process
may be reconstructed by comparing the faces of
different races, from the projecting muzzles, very

large mouth, broad flat nose and retreating chin

OUR ANCIENT RELATIVES

of some of the Tasmanians (Fig. 10, Frontispiece) to
the narrow, forwardly -projecting, pointed nose and
pointed chin of the Alpine, European type (Fig. 11
Frontispiece).

Fig. 48. Evolution of the Hu-
man Skull: Ten Structural
Stages.

I. Lobe-finned fish, Devonian
age (after Traquair, Watson, Bry-
ant). II. Primitive amphibian,
Lower Carboniferous (after Wat-
son). III. Primitive cotylosau-
rian reptile, Permo-Carboniferous
(after Broili, Williston, Watson).
IV. Primitive theromorph reptile,
Permo-Carboniferous (after Willis-
ton). V. Gorgonopsian reptile,
Permian (after Broom). VI.
Primitive cynodont reptile, Trias-
sic (after Broom, Haughton). VII.
Primitive marsupial, Upper Cre-
taceous (after Matthew) VIII.
Primitive primate, Eocene (after Gregory)
chimpanzee), Recent. X. Man, Recent.

IX. Anthropoid (female

For details, see pp. xxii, xxiii.
78

Fig. 49. Evolution of the
Human Skull Roof.

Same series as in Fig. 48, except
that in No. VII, the recent opos-
sum instead of its fossil ancestor
is used.

For details, see p. xxiii.

Fig. 50. Evolution of the
Human Jaw-bones.

Same series as in Fig. 49.

jFor details, see p. xxiii.

Fig. 51. Evolution of the Cib-

CUMORBITAL BoNES.

Same series as in Fig. 49.
For details, see p. xxiii.

Fig. 52. Evolution of the
Bones Behind the Jaws.

Same series as in Fig. 49. Figures
48-52 give excellent examples of " Wil-
liston's law" of the progressive elimi-
nation of skull elements in passing
from fish to man.

For details, see pp. xxiii, xxiv.

PART II

CONCISE HISTORY OF OUR BEST
FEATURES

The Bony Framework of the God-Like Mask

To review at this point the history of the bony
framework of the face, we note that the human
skull as a whole is a complex consisting of a chon-
drocranium, or inner skull, which is preformed in
cartilage, and an outer shell of dermal bones,
formed in membrane. The chondrocranium com-
prises the base of the skull, the sphenoid bone and
the olfactory and otic capsules. The outer, or
dermocranium, comprises: (a) the roofing bones
(nasals, frontals, parietals, and the membranous
part of the supraoccipital) ; (b) the orbital elements
(lacrymal, jugal, or malar) ; (c) the squamous part
of the temporal bone; (e) the maxillary elements
(upper and lower jaw bones) ; (f ) the palatal bone
and the internal pterygoid plate of the sphenoid;
(g) the vomer.

The illustrations submitted herewith (Figs.

OUR FACE FROM FISH TO MAN

48-53) set forth a few of the facts which have
convinced modern anatomists that man, like other
mammals, was not created at one stroke, but that
he reached his present condition by gradual stages
of modification, which, thanks to the unremitting
labors of many palaeontologists and anatomists,
now appear to be fairly well understood. None of
these stages is hypothetical; they are either known
fossil forms or are the surviving and little-modified
descendants of known fossil forms.

From the imperfect nature of the fossil record
we can never expect to recover the infinite number
of links in the direct line of ancestry of man or of
any other mammal. The record affords us only
successive structural stages that are more or less
nearly related to the main line of ascent from fish
to man.

The story told in these illustrations has not been

invented by the writer. It has slowly revealed

itself as the palaeontologists and anatomists of a

century past have gradually unearthed it. During

the past fifteen years great progress has been made

all along the line of stages I to X, either in the

discovery of hitherto unknown or little-known

forms, or in the determination of the sutural

>r^

*> »

hhPh o c<

s^ ax

OUR FACE FROM FISH TO MAN

limits of the individual bones, or in the vital
problems of determining the systematic relation-
ships of each of the forms figured and of the
groups that they represent. Recent palaeontolo-
gists who have contributed especially to these
subjects include D. M. S. Watson (in connection
with Stages I, II, III, V, VI), Bryant (in connec-
tion with Stage I), Williston (in connection with
Stages III, IV), Broili (in connection with Stage
III), Broom (in connection with Stages V, VI),
Haughton (in connection with Stage VI) , Matthew
(in connection with Stage VII), Gregory (in con-
nection with Stages VIII, IX). The drawings,
like most of the others in this book, were skilfully
executed by Mrs. Helen Ziska, working under the
constant advice and supervision of the author.
For whatever errors the figures may still bear, after
many appeals to the original data, the writer alone
therefore must be held responsible.

To recapitulate, the outstanding changes in the
lateral view of the skull from fish to man appear
to have been as follows:

Of the bones on the roof of the skull (Fig. 49),

namely the nasals, frontals, parietals, interparietals

(or dermo-supraoccipitals) and tabulars, only the

OUR BEST FEATURES

last disappear entirely in the mammals. As the
brain enlarges these roofing bones are lifted into
greater prominence, the frontals, parietals, inter-
parietals and occipitals becoming the dominant
elements in the great vault of the human skull.

The superior maxillary bone (Fig. 50) begins as
a slender, vertically shallow element, but by the
time of the early mammal-like reptiles (Fig. 50 V)
it has extended dorsally and gained contact with
the nasals. In the mammals (Fig. 50 VII-X) its
dominance is still more pronounced; one fork
reaches the frontals while another fork finally
separates the lacrymal from the jugal and the
whole bone becomes shortened antero-horizontally
and deepened vertically. In the anthropoids and
man the premaxillse early unite with the maxillae.

The inferior maxillary (dentary) at first is
confined to the anterior half of the mandible. In
the higher mammal-like reptiles it becomes dom-
inant, the post-dentary elements retreating before
it. In the earliest mammals the ascending ramus
of the dentary effects a new contact with the
squamosal, the temporo-mandibular articulation,
which is transmitted without further essential

modification to man.

OUR FACE FROM FISH TO MAN

Of the bones around the eye (Fig. 51), originally
five in number, three (the prefrontal, postfrontal,
postorbital) are eliminated by the time of the
earliest mammals, so that man inherits only two
of the original five, namely the lacrymal and the
jugal or malar.

The temporo-mandibular series (Fig. 52), orig-
inally including eight bones (the intertemporal,
supratemporal, squamosal, quadra to-jugal, sur-
angular, angular postsplenial, splenial), suffers
gradual reduction, until in the earliest mammals,
as in man, only the squamosal remains, at least in
the lateral view of the skull. In the mammals the
squamosal has fused with the enlarged periotic
mass and in the anthropoids and man the tym-
panic is added, the whole complex forming the
temporal bone.

At every successive stage of evolution advances
in skull structure were dependent upon improve-
ments in the brain itself, upon shiftings and
enlargements of the parts containing the sense
organs, upon modifications of the jaws and teeth,
accompanying or accompanied by changes of
habits. The skull in turn is closely integrated
with both the active and the passive elements of

OUR BEST FEATURES

the locomotor apparatus, a topic which will be
developed elsewhere.

To each of the stages described above man owes
certain "basic patents," or adaptive improve-
ments which have been of critical importance in
his survival. Thus to certain far-off Devonian
air-breathing fishes man owes the general ground-
plan of the vertebrate skull, the combination of
primary "gill-arch" jaws with sheathing or outer
jaws, and each and every one of the twenty-eight
normal skull bones which he still retains.

Next, he is indebted to the first amphibians for
partially solving the innumerable problems caused
by emergence from the water. These old pioneers
cast off the whole series of bones that covered the
branchial chamber and made for themselves an
ear-drum out of the skin around the notch where
the opercular was formerly located. The early
reptiles safeguarded most of the inheritance from
their semi-aquatic ancestors, dropping only the
inter- and supra temporals. To the first of the
mammal-like series man owes the beginnings of
his temporal fossa and zygomatic arch, and the
dominance of the superior maxilla. From the

higher mammal-like reptiles he has inherited the

OUR FACE FROM FISH TO MAN

further development of the temporal fossa and
especially the dominance of the inferior maxillary
or dentary bone of the lower jaw. To these
progressive pro-mammals man can render thanks
for the differentiation of his dentition into incisors,
canines, premolars and molars, and apparently
he can also thank them for the reduction of the
numerous successional teeth to two sets, corre-
sponding to the milk teeth and the permanent set.

The earliest mammals invented one of the most
useful features of man's skull by eliminating from
the masticatory apparatus all the elements lying
behind the dentary and by establishing the
temporo-mandibular joint. They also cast off
the reptilian prefrontal, postfrontal and postorbital
bones and cleared the way for the final simplifica-
tion of the bony scaffolding of the face.

To the earliest primates, well schooled in
arboreal life, man owes the first steps in the
glorification of the eyes, which become increasingly
dominant. These still lowly but thrifty forebears
made good the loss of the reptilian postorbital
bar by elaborating a new one from conjoining pro-
cesses from the frontal and jugal (or malar) bones.

But still greater was our debt to the arboreal

OUR BEST FEATURES

pro-anthropoids, those intelligent beings who
elected to develop sight at the expense of smell.
These skilled acrobats, moving in a vertical
position, met and solved a new series of problems
connected with the turning downward of the
skull upon the upright column. They also made
the first notable attempts to shorten and deepen
the face and even took a long step toward enlarg-
ing the brain and brain chamber.

Starting with these and many like advantages
gained during a long training in arboreal life, it
was the task of our relatively nearer precursors
(beginning possibly in Miocene times, or earlier) to
re-adapt all these arboreal adaptations for a life
on the ground and to take the final steps upward
that have brought humanity to its present levels
of intelligence.

Wholly ignorant of the facts, the ancient Jewish

'priests indulged themselves in the fancy that man was

made in the image of Ood; but modern science shows

that the god-like mash which is the human face is

made out of the same elements as in the gorilla; and

that in both ape and man the bony framework of the

face is composed of strictly homologous elements,

inherited from a long line of lower vertebrates.

OUR FACE FROM FISH TO MAN

Fish-Traps and Faces

the first mouths

From air-breathing fish to man the general

course of evolution seems clear enough, at least in

its broad outlines. But when we inquire whence

myomere

•Sexglands

spinalcord notochord

giil-slitsl mouih
cUiatedortove

Fig. 54. Anatomy of the Lancelet, the Most Primitive Living
Chordate Animal (after Delage and Herouard).

A. Entire animal, seen as a semi-transparent object; B. Longitudinal
section. For details, see p. xxiv.

came the fish, the evidence while extensive is

somewhat ambiguous and there is room for sharp

differences of opinion. On the one hand, there is

Professor Patten, who derives the whole vertebrate

series from very ancient jointed animals remotely

allied to the modern scorpions and Limulus; on

the other hand, there are the more orthodox

OUR BEST FEATURES

zoologists, who infer that the greatly simplified
form Amphioxus (Fig. 54), together with all the
vertebrates, represent offshoots of some still undis-
covered stock that also gave rise to the acorn-
worms (Balanoglossus), the starfishes and certain
other peculiar groups. According to this view,

Fig. 55. Larv^ of Echinoderms: Sea-cucumber (A), Starfish

(B) AND OF THE "AcORN-WORM" (AFTER DELAGE AND HeROUARd).

For details, see p. xxv.

the common ancestors of all these diversified

groups were exceedingly simplified, free-swimming,

marine organisms, consisting chiefly of a digestive

tube bent at a right angle and enclosed in a thin

balloon-like tissue, more or less folded into plaits

and provided with strips of cilia, by the lashing

of which the floating bag moved slowly through

the water. Such forms (Fig. 55) are found living

today as the larvae or young stages of starfishes,

OUR FACE FROM FISH TO MAN

sea-cucumbers, and also of the acorn- worm Balan-
oglossus. The mouth of these forms is the original
mouth of the primitive gut or digestive tract.

There is evidence from embryology that the
mouth of the vertebrates is a compound structure

pineal
jtai/r

notochorcC

nasal hypoTohyns mouth '-cavity
pit

mouth-
carity

heart

Fig. 56. Inner and Outer Mouth Pouches in Embryo Verte-
brates: Larval Lamprey (A) (after Minot); Embryo
Rabbit (B) (after Mihalcovics).

For details, See p. xxv.

formed from the union of a down-pocketing of the

outer layer or ectoderm, meeting a pouch growing

out from the primitive gut. These inner and

outer mouth pouches in the early embryos of

lampreys, sharks and higher vertebrates, are

similar to the inner and outer pouches that give rise

to the gill openings, with which indeed they are

supposed to be homologous. Moreover Stensio

has recently shown that in the cephalaspid

OUR BEST FEATURES

ostracoderms (Fig. 57) the mouth cavity was in
series with the cavities of the gill openings and was
probably homologous with them.

The predecessors of the vertebrates probably
fed upon small organisms and organic matter,

Fig. 57. Attempted Restorations of the Mouth and Gill Region
of Two Cephalaspid Ostracoderms by Stensio.

For details, see p. xxv.

which were scooped into the mouth cavity and
may have been passed along to the stomach by
the lashing of cilia located in a groove, as in the
living Amphioxus (Fig. 54).

This method of ingestion by means of cilia may
also have been practised by some of the ostra-
coderms, the earliest known forerunners of the

OUR FACE FROM FISH TO MAN

vertebrates (Figs. 4, 57). Such food habits would
seem reasonable both for those ostracoderms, like
Pteraspis (Fig. 4D), which had narrow mouths
placed below a long rostrum and therefore adapted
for feeding in the mud, and for those like Tremat-
aspis (Fig. 4B, C) in which the fore part of the
body was flattened into a broad rounded shovel
and the mouth was a wide slit-like opening at the

Fig. 58. Swift-moving Ostracoderm from the Silurian
of Norway (after Kiaer).

For details, see p. xxv.

front border of the head. In Cephalaspis (Fig.

57B) also the mouth appears to have been in

series with the gill-arches.

But there were still other ostracoderms of the

order Anaspida (Fig. 4A), in which the body-form

seems adapted for swift movement through the

water and in which the mouth, while not too large

to be powerful, was strengthened by a bony strip

with a knob on its front end. Such ostracoderms

may have already embarked on the career of

OUR BEST FEATURES

piracy which seems to have characterized the
more remote ancestors of man for countless ages.
But up to this point in their evolution true teeth
had not been attained by the early predecessors
of the vertebrates.

WV»^Wj#W?'r I % ' \ !■!■; rl-, '.' ■

nostril drain

Sfiinalcord
notochord

mouth
cavity p

yillslits

intestine

Fig. 59. A Modern Descendant of the Ostracoderms.

A. Adult lamprey (after Jordan and Evermann); B. Longitudinal
section of larval lamprey, enlarged (after Goodrich).

THE BEGINNINGS OF TEETH

The ostracoderms as a whole may be transitional

between the method of "ciliary ingestion" and

the devouring of living flesh by the existing

cyclos tomes (lampreys, hags), which Stensio has

OUR FACE FROM FISH TO MAN

shown to be the highly specialized, eel-like, and
in some respects degenerate derivatives of the
ostracoderms of Silurian times. Even today (Fig.
59) in the early larval lamprey (Ammocoetes stage)
the pharynx is provided with a prominent "ciliated
groove," which (like that of Amphioxus) appears
to be reminiscent of the earlier days of feeding on
microscopic organisms; the adult lamprey, on the
other hand, is a cruel pirate, rasping off chunks
of flesh from the sides of helpless fishes and occa-
sionally eating its way, it is said, into their
interiors, finally reducing them to floating shells.

The lampreys and their allies are enabled to
carry on their nefarious business by means of
thorny teeth, set in concentric rows about the
mouth and flanking a protrusile rasp, which is
likewise covered with horny teeth and can be
drawn back and forth like the rasp of a whelk.

The teeth of the lampreys (Fig. 60A) are of
extraordinary interest, since they have always
been regarded as representing a very early stage
in the evolution of the teeth of vertebrates. Each
tooth consists of a thick, horny, epithelial thorn
with a pulp cavity within, which is ready to grow

another thorn as soon as the outer one is broken

OUR BEST FEATURES

first homy tooth
epiderrnti
be math tooth

epidermis

germ,
ofseconti^k
tooth 2. . . > . ■

nutritive papiita of
J\ dermis'

Fig. 60. Development of Teeth in Lampeet (A) and Shark
(B, C, D). (After Goodrich.)

For details, see p. xxvi.

OUR FACE FROM FISH TO MAN

off or shed. Nevertheless the teeth of the higher
vertebrates probably arose not from horny epi-
thelial teeth like those of the modern lampreys,
but from enamel-covered shagreen denticles such
as covered the whole body of Lanarhia, one of the
Scotch Silurian ostracoderms. In the sharks (Fig.
60B, C, D) each little shagreen denticle on the
surface of the skin consists of a little cone in
which a porcelain-like layer of "enamel" is laid
down between the epithelial covering and the
pulp cavity. These shagreen denticles, together
with the stratified bony deposits in the deepest
layers of skin, gave rise not only to the teeth of
higher vertebrates but also to the enamel-covered
bony plates that cover the braincase, the bony
tooth-bearing plates that cover the primary
cartilaginous jaws and the bony tooth-bearing
plates on the roof of the mouth, both in the air-
breathing, lobe-finned fishes and in their successors,
the earliest amphibians.

These enamel-covered plates were also homolo-
gous with the bony ganoid scales on the surface of
the body.

Thus we are again reminded of the remarkable

potentialities of the many-layered skin in the

100

OUR BEST FEATURES

ancestors of the vertebrates, since it gave rise in
different groups to horny thorns, to shagreen
denticles, to true stratified bony scales, to enamel-
covered skull plates, as well as to many different
kinds of sense organs.

Nor can it be too often pointed out that the
whole organization of primitive vertebrates was
adapted for the pursuit and capture of living prey,
that sharp teeth were made from the shagreen of
the skin, first for holding and then for cutting
living prey, that in every geological age until we
reach the primitive anthropoid stock of relatively
recent times, the herbivorous forms, derived from
the more primitive carnivores, acquired various
types of specialized teeth which could never have
given rise to the higher carnivorous types. Any
hypothesis that would derive the earlier carniv-
orous vertebrates from herbivorous predecessors
would be definitely contradicted by all the avail-
able evidence afforded by a comparative study of
the brain, sense organs, the locomotor apparatus
and the digestive system.

After a century of intensive research we can

only speculate, almost idly, as to what may have

been the mode of origin of the mouth, jaws and

101

OUR FACE FROM FISH TO MAN

teeth below the ostracoderm grade of evolution.
But when we reach the grade of evolution repre-
sented by the shark, we find that the shark stands
unquestionably nearer to man in the construction of
its jaws and teeth than it does to any known group of
invertebrates; while between shark and man many
intermediate conditions of the mouth are definitely
known.

THE PRIMARY JAWS

The gill pouches of fishes and of the embryos of
higher vertebrates, including man, are supported
by cartilaginous bars (Figs. 7, 8), the so-called
"visceral arches," and the mouth pouches of
sharks and embryo vertebrates are likewise sup-
ported by cartilaginous bars, the oral cartilages,
which have every appearance of belonging in
series with the gill arches. The primary upper
jaw cartilages, one on either side, are called the
palatoquadrate cartilages, while the primary lower
jaw cartilages are called Meckel's cartilages, or the
mandible. The "labial cartilages" in front of
the jaws (Figs. 7, 8) are possible remnants of at
least one " premandibular " arch.

In the predecessors of the sharks, we may infer,

102

terrtpera.1

■ •depressor
'manc(i6u.!cp
pterygoid

■rnasseter

tern vera I

'eprtssor

masseter

pterygoid

nOyastn'p

pterygoid ^floral

depressor

masseter

temporcd tevatormeu(llm.sup
(ac/d.mandl-) /

letrcdor
t\ maxdtasup.

'yiirtrrp
■yrrdstefer

Fig. 61. Evolution of the Jaw Muscles from Fish to Man.

I. Shark (data from Allis). II. Lobe-finned ganoid (after L. A.
Adams). III. Primitive amphibian (after L. A. Adams). Restora-
tion. IV. Primitive mammal-like reptile (skull mainly from Broom).
Restoration. V. Advanced mammal-like reptile (after L. A. Adams).
Restoration. VI. Primitive marsupial (after L. A. Adams). VII.
Primitive primate. VIII. Chimpanzee. IX. Modern man.
For details, see p. xxvi.

103

OUR FACE FROM FISH TO MAN

none of these "visceral arches" (labial cartilages,
jaws or gill arches) were connected with the brain-
case except by connective tissue and as the living
prey was presumably small there was no need of
special bracing for these arches. But as the race
grew larger the size of the prey likewise increased
and convulsive swallowing efforts were made by
the fish to force the prey past the region of the gill
pouches down into the stomach. At the same
time the contractile muscles around the whole
branchial series grew stronger, those attached to
the future jaw arches increased faster than their
fellows and so did the future jaws themselves.
In this way the jaw muscles of the shark and of
higher vertebrates (Fig. 61) were apparently
derived by enlargement from muscles correspond-
ing to the constrictor muscles of the gill arches.

For a long time the primary upper jaw was
suspended from the skull mainly through its
attachment to the second or hyoid arch (Fig. 62A)
but in the amphibians and higher vertebrates the
primary upper jaw itself becomes attached to the
skull (Fig. 62, B, C). When large tooth-bearing
bony plates came to sheath and cover over the

primary upper and lower jaws they gradually

104

olfactory
'ipsute.

fiyomandiduta.)

* fssffiisgr »* ****»

epipTpryg'oid

brain-case epipterygratd

rax

^uadrctfe

yfiamosal

Fig. 62. Methods of Attachment of the Pkimary Upper Jaw
to the Under Side of the Skull.

In C the bony mask covering the temporal region is cut through and a
part of it removed to show the primary upper jaw and its relations to
the braincase. For details, see pp. xxvi, xxvii.

105

OUR FACE FROM FISH TO MAN

supplanted them, at least in the tooth-bearing
regions. In mammals (including man) clear traces
of the primary upper jaw may be found in early
embryonic stages of development (see Keith,
Human Embryology and Morphology, 1921, pages
138, 148, 172).

THE RISE OF THE SECONDARY JAWS AND
THEIR TEETH

Up to the present time we have been dealing

with the origin and early evolution of the primary

upper and lower jaws, but in the higher vertebrates,

including man, these primary jaws are completely

overshadowed and masked by the secondary jaws.

In the sharks the secondary jaws are represented

merely by the skin that is wrapped around the

primary jaws, or palatoquadrate and Meckel's

cartilage, both on the outside and on the inside of

the mouth. In the sharks this skin has no bony

base but in the higher fishes and early amphibians

the primary upper and lower jaws are covered

with many -layered bony plates originally provided

with a porcelain-like surface of "ganoine" and

usually bearing numerous teeth. In the early

lobe-finned, air-breathing fishes (Figs. 11, 12)

106

OUR BEST FEATURES

these plates are of exactly the same nature as the

roof-bones of the skull and the scales on the body.

Thus arises the hard "facial mask" so often

referred to in the preceding pages.

As used in this book the term "secondary jaws"

is limited to the tooth-bearing plates covering the

external borders of the primary upper and lower

jaws. There are three of these elements on each

side of the head throughout the series (Fig. 50)

from fish to man and their amazing constancy is an

item of evidence of the unity of plan and origin of

all the higher vertebrates. The first of these

secondary jaw elements is the premaxilla, one on

each side of the mid-line, at the front end of the

jaw; this is followed by the maxilla, one on each

side behind the premaxilla?. When we compare

the under side of the skull (Fig. 63, I, II) of one

of the fossil lobe-finned (crossopt) ganoids of the

Devonian with that of one of the early amphibians

of the Coal Measures, we can hardly doubt that

the premaxilla and maxilla of the former are each

completely homologous with the corresponding

element in the latter. And from the earliest

amphibian to man they can be traced in convincing

detail (Figs. 50, 53).

107

OUR FACE FROM FISH TO MAN

The third of the secondary jaw elements is the
dentary bone, one on each side of the lower jaw.
In the lobe-finned or crossopt fishes this bone,

Fig. 63. Under Side of the Skull of Devonian Fossil Fish (A)

and Primitive Fossil Amphibian (B). (A after Bryant

and Watson; B after Watson).

The secondary upper jaws are on the margins; the primary upper
jaws are largely covered by tooth-bearing plates of the primary palate.
For details, see p. xxvii.

while bearing a stout series of teeth, had not yet
assumed the primacy it acquired in later types.
We have already (pages 36-39) traced its progress
in the mammal-like reptiles and have seen it
encroach on the other membrane bones of the

lower jaw until it finally secured a contact with the

108

OUR BEST FEATURES

squamosal bone covering the side of the temporal
part of the skull, by which time it had succeeded
in crowding its fellows quite off the map.

Meanwhile, how did the crossopts and early
amphibians acquire the strong teeth with which
they carried on their predatory lives? In the
most primitive sharks (Fig. 5) the shagreen-bearing
skin is rolled around over the upper and lower jaw
cartilages and as the old teeth are broken off the
new teeth are gradually pushed up into place on
the edge of the jaws in a continuous succession.
In the typical sharks the tooth-bearing roll of
skin lies in a depression in the calcified cartilaginous
primary upper and lower jaws, but the teeth are
not separately connected with the jaws and when
in use are tied in place only by the strong dental
ligament attached to their bases.

In the crossopts (lobe-finned fishes) of the

Devonian period the primary upper jaw (palato-

quadrate), now completely saturated with bone

cells, is covered with bony dermal tracts bearing

teeth, some very large and compressed, some

small and conical. In front there is also a pair of

tooth-bearing dermal plates, the pre vomers, on

either side of the mid-line. Likewise the secondary

109

OUR FACE FROM FISH TO MAN

upper jaws, the premaxilla and maxilla, bear
compressed conical teeth. The dentary plate of
the lower jaw (Fig. 64) covering the outer side of
the primary lower jaw or Meckel's cartilage, bears
a row of conical teeth which fit between the
marginal teeth of the secondary upper jaw and
the larger teeth on the dermal plates covering the
primary upper jaw. Thus we have the teeth of
the secondary upper jaw over-hanging or biting
outside of those of the dentary or lower jaw, an
arrangement that persists throughout the sub-
sequent series upward to the primitive mammals,
traces of it even being preserved in man. The
coronoid bones, covering the inner side of the
primary lower jaw, in the lobe-finned fish bear large
teeth which doubtless sheared into the struggling
prey and pressed it against the large teeth on the
roof of the mouth. Thus neither the Meckel's
cartilage, or primary lower jaw, nor the palato-
quadrate, or primary upper jaw, now have any
direct relations with the teeth, which are supported
entirely on their own bony plates, as they are in
all higher vertebrates, including man. The pri-
mary lower jaw from this point onward takes a

subordinate part, except that its nearer (proximal)

110

tUUUAituiMMJM.

TXt ^^U&

sura/tf

car{- corz

pos/ol tyl
sumncr

tf/c/c.

iAfeck)

dn,-

£Pr \

jurany

sarf-(AferA)

A/ttft.

Spl pc&pl any/ preart

Meek eft carftlaae

sj/ranff

Pig. 64. Right Half of the Lower Jaw of Lobe-finned Fish

(A, C) and Primitive Fossil Amphibian (B, D), and Recent

Turtle Embryo (E). (A, C, after Watson; B, D, after

Williston; E, after Parker.)

For details, see pp. xxvii, xxviii.

Ill

OUR FACE FROM FISH TO MAN

end, after becoming ossified (after which it is
called the articular bone) serves for the main
articulation of the lower jaw with the primary
upper jaw; this arrangement persists from the
crossopt fishes up to the most advanced mammal-
like reptiles, which are the immediate predecessors
of the mammals.

Each tooth of the above described fossil crossopt
fishes consists essentially of an enlarged cone with
an open pulp cavity, the sides of the cone being
very deeply infolded toward the base, so that in
cross-section the primary and secondary folds give
rise to the characteristic labyrinthodont pattern
(Fig. 18). The surface of the tooth is deeply
covered with enamel-like ganoine, which is folded
into the primary and secondary folds, and the
interior consists of dense, stratified bone or
dentine. The derm bone which bears the tooth
is strongly attached to it and is folded into its
sides along with the primary and secondary folds.

This labyrinthodont mode of attachment of the

teeth to the jaw bones is a far more primitive and

important method than any of those commonly

cited in textbooks on comparative dental anatomy,

which usually describe only the either degenerate

112

OUR BEST FEATURES

or highly specialized modes of attachment found
in modern amphibians and reptiles, since it was
the starting-point of the conditions found in the
higher vertebrates, including man.

To sum up then, the lobe-finned fishes exhibit a
great advance upon the sharks toward the am-
phibians and higher vertebrates in the following
respects: (1) the primary upper and lower jaws
are now covered with tooth-bearing bony plates,
only the back part of the primary upper jaw
(forming the quadrate bone) and of the primary
lower jaw (forming the articular bone) being
exposed and forming the articulation between the
upper and lower jaws; (2) the secondary upper
and lower jaw (premaxilla, maxilla, dentary) for
the first time appear as ossified tooth-bearing
plates, which may be compared directly with those
of amphibians and higher vertebrates; (3) each
tooth represents an enlarged denticle with the
base infolded into the labyrinthodont pattern.
It is fastened to the bone by the infolding of the
latter into the labyrinthodont folds; (4) thus the
upper and lower jaws as a whole are of complex
construction, including a large number of distinct

bony plates, some of which disappear as we pass

113

OUR FACE FROM FISH TO MAN

to the higher vertebrates, but three of which
(premaxilla, maxilla, dentary) persist even in man
(Fig. 50).

All these highly predatory adaptations were
transmitted by heredity to the oldest known
amphibians of the Coal Measures, which are at
the very least rather close relatives if not actual
descendants of the osteolepid crossopts. The
chief advance in these oldest amphibians is the
elimination (Fig. 17) of the whole series of plates
connected with the opercular tract and consisting
of the plates named operculum, suboperculum,
interoperculum, preoperculum, and a series of
small lateral gulars or branchiostegals. All these
were sacrificed when the amphibians eliminated the
internal gills in the adult stage.

The loss of these plates not only constitutes a
fine example of Williston's law of the progressive
reduction in the number of bony elements, as we
pass from fish to man, but also serves to bring out
the fact that evolution proceeds fully as much by
the loss of superfluous parts as by the further
differentiation of those that remain (Figs. 50, 52).

Many of the amphibians adopted the easy

method of lying in wait in the water for their prey,

114

OUR BEST FEATURES

perhaps even with their mouths open, and then

suddenly engulfing it in a living trap. Such a

line of specialization leads often to wide flat skulls

and very shallow, widely-bowed jaws set with rather

small teeth on the margins and a few larger

piercing teeth on the roof of the mouth, as in the

great labyrinthodonts or stegocephalians of the

Permian and Triassic periods. Others, in which

the jaws became very long and narrow, actively

swam in pursuit of fishes. But those amphibians

{e.g. Fig. 48 II) which were destined to give rise

to the line of ascent to man, avoiding both these

extremes, had jaws of only moderate length and a

skull of moderate width and considerable depth,

especially toward the rear end. At first they

retained the teeth on the roof of the mouth (Fig.

53, II-IV) but in the series of reptiles (Fig. 53, V)

that finally culminated in the cynodonts (Fig.

53, VI) and probably in the mammals (Fig. 53,

VII), the teeth on the roof of the mouth, that is,

on the primary upper jaw, were eliminated and the

marginal teeth on the secondary jaws acquired the

typical dog-toothed or caninif orm type of predatory

animals that pursue their prey on land.

From this condition there are intermediate stages

115

OUR FACE FROM FISH TO MAN

to the essentially mammal-like dentition of the
cynodonts (Fig. 50 VI), in which the adult denti-
tion, as in man and other mammals, consists of
incisors, canines, premolars and molars, and in
which the dentition was apparently reduced to
two sets corresponding to our milk and permanent
teeth. Moreover, each tooth in the cynodonts
was set in a distinct socket as in the mammals.
Hence these reptiles had already traveled far on
the long road from fish to man.

We have followed some of the progressive
changes in the jaws of these forms, in which the
dentary bone finally became the predominant
element and gained contact with the squamosal
bone of the skull (Fig. 21), while the bones behind
the dentary were reduced to slender proportions
(Fig. 52). These changes, however they may
have been initiated, were obviously associated
with a great development of the temporal, masseter
and pterygoid muscles of the jaws (Fig. 61),
which have very strongly braced areas of origin
and attachment. To the activity of the temporal
muscle we apparently owe the first appearance of
the temporal fossa (Fig. 48 IV) in the shell of bone

that formerly roofed over the jaw muscles, while

116

OUR BEST FEATURES

to the increase in size of the pterygoid muscles
may safely be ascribed the pinching together of
the opposite pterygoid bones and the development
of a high bony crest on the mid-line of the base
of the braincase (Fig. 53 V).

Turning again to the teeth, we may summarize
their early history as follows: In some of the
Silurian ostracoderms (Lanarkia) the teeth of
later vertebrates are represented by thorny sha-
green denticles embedded in the skin all over the
surface of the body, but the ostracoderms them-
selves did not have teeth in the mouth. In the
sharks the skin on the inside of the mouth and
jaws carries the teeth, which represent only
enlarged dermal denticles. In the sharks the
tooth-bearing skin on the inner side of the jaws
is rolled inward in a spiral manner and as the old
teeth are broken off the new ones unwind or rotate
into place.

In the lobe-finned or crossopt fishes, representing

the ancestors of the amphibians, at least the larger

teeth arise from pockets of bone sunk below the

surface of the bony enamel-covered skin. In these

forms the bases of the teeth are deeply and

complexly infolded and the pockets of bony skin

117

OUR FACE FROM FISH TO MAN

are infolded into the bases of the teeth. The
teeth succeed each other in an oblique series.
In Seymouria, a fossil reptile from the Permo-
Carboniferous of Texas, which is almost on the
borderline between the primitive amphibians and
all the higher levels of vertebrates, clear traces of
the labyrinthodont method of tooth-attachment
are still visible, but by the time of the higher
mammal-like reptiles all traces of the older method
had been lost and the teeth are set in sockets as in
the mammals, including man.

ORIGIN OF THE MAMMALIAN PALATE

No less important in determining the course of
future evolution in the mammals and in man were
the progressive changes in the palatal region
(Fig. 53). In the early amphibians the air taken
into the olfactory chamber was passed through
a pair of tubes opening by the choanse (Fig. 53
II, cho.) or internal nostrils, into the fore part of
the roof of the mouth, and from this point the
inspired air was practically swallowed, or forced
backward by the action of the throat muscles to
the opening of the windpipe. In the early mam-
mal-like reptiles (Fig. 53 V) the choanse opened

118

OUR BEST FEATURES

into a depression or chamber lying considerably

above the general level of the tooth-bearing

margins of the upper jaw and they may have

been the beginning of a fleshy palate. In the

higher mammal-like reptiles or cynodonts (Fig.

52 VI) a secondary palate or bony roof of the

mouth was formed by horizontal ledges that grew

out from the palatine (pi) and maxillary (mx)

bones and formed a shelf below the chamber where

the internal nostrils opened. Very possibly the

increasing muscular power and mobility of the

tongue, which pressed against the inner side of the

upper tooth-bearing bones, may have favored the

evolution of bony shelves from the palatine and

maxillary bones. In the mammals (Fig. 52

VII-X) (including man) this process is carried

much further so that in the adults the bony palate

is prolonged much farther backward. To the

rear end of this bony palate the soft palate was

attached. In this way the naso-pharyngeal air

passage was formed, by means of which the

inspired air is delivered almost directly to the

windpipe, instead of having to pass through the

food-containing cavity of the mouth. All this is

associated in the higher mammal-like reptiles and

119

OUR FACE FROM FISH TO MAN

early mammals with the very active respiration
of carnivorous animals.

The anti-evolutionists may be interested to
learn that at a very early stage of its development
the human embryo (Fig. 65) passes through a stage
in which the olfactory capsules, like those of sharks,
have no internal opening on the palate but are

OLFACTORY
P/T
fDREBMM^^ EYE

MCOBSO//M
OWA/V \

Fig. 65. Early Embryonic Stages in the Development of the

Nose in Man (after Keith).

merely extended backward and downward toward

the mouth. Later (Fig. 66) the choanse, or internal

openings of the olfactory capsules, develop in the

fore part of the roof of the mouth, but there is only

the beginning of a secondary palate and the

conditions in the reptiles (Fig. 66B) are recalled

(Keith, Corning).

In this connection Keith (1921, pp. 158, 159)

summarizes the evolution of the human face as

follows :

120

nostril

groove
to mouth

brain ,

premax /[ W& ^

ax. / ^^£*^f\

^-Fustacfiidrz
roof of pharynx tube S

r^ J mirier.

J).

Jacobsonb
cartilage
palate
r-\- vomer

Jacobson's
organ

palate

Fig. 66. Comparative Anatomy of the Human Palate.

Recent shark, showing groove from nose to front of mouth. (After
Keith.)

Lizard, in which internal opening (choana) from the nose opens in
the forepart of the mouth cavity. (After Plate.)

Lion pup with cleft palate, recalling in form the palate of reptiles;
showing internal opening of the nose (indicated by the arrow-
point) in the forepart of the mouth cavity. In this abnormal
specimen the secondary palate has failed to grow over to the
midline. (After Keith.)

Human embryo at the end of the sixth week, showing the secondary
palatal plates beginning to grow in toward the midline and the
"primitive choana?" (arrow-point) still exposed in the forepart
of the roof of the pharynx. (x\fter Keith.)
(B, from Allgem. Zool., Gustav Fischer.)

121

OUR FACE FROM FISH TO MAN

In our survey of the neural part of the human cranium
we have seen that its outstanding features are the result
of a great cerebral development. When, however, we turn
to the facial and pharyngeal parts of the skull and head,
we find that the factors which have determined their shape
are related to the functions of smell, respiration and of
mastication. It is unnecessary to again insist on the fact
that the human embryo, in the latter part of the first
month, shows a resemblance to a generalized type of fish;
it possesses the basis of a branchial arch system. As in
the fish, the olfactory organ is represented by a pair of
pits or depressions, which at first have no communication
with the mouth. In some forms of fish — certain rays and
sharks — a channel is formed between each olfactory pit
and the mouth. The functional meaning of such a channel
is evident; the water imbibed is sampled by the nose
before entering the mouth. When pulmonary breathing
was introduced, as in Dipnoean fishes, the open naso-
buccal channel became enclosed by the union of its bound-
ing folds. In amphibians, reptiles and birds the naso-
buccal channel becomes dilated to form a true respiratory
nasal passage, and the parts bounding the passage unite
on the roof of the mouth to form the primitive palate.
In Fig. 152 the parts entering into the formation of the
primitive palate are shown. They are three in number:
(1) a premaxillary and vomerine part developed between
the nasal passages; (2) a right and left maxillary part,
laid down on the lateral or outer aspect of each passage.
In mammals a fourth element is added to the primitive
or reptilian palate, and in this way the mammalian mouth
is separated from the nasal respiratory passage, and can
serve the purposes of mastication and suction. Thus in
the evolution of the face there have been three distinct
stages: (1) a piscine, in which the nose and mouth were
formed independently; (2) an amphibian stage, where the
nasal respiratory passage opened on the roof of the mouth;
(3) a mammalian stage, in which it opened in the naso-

122

OUR BEST FEATURES

pharynx. In the development of the human embryo we
see these three stages reproduced.

EVOLUTION OF THE TONGUE AND
RELATED STRUCTURES

In Amphioxus (Fig. 54) there is no tongue and

in the lampreys and hags the so-called tongue

with its enclosed cartilages probably represents

the lower jaw of the shark (Stockard, Goodrich).

In the shark the folding up of both the jaw

cartilages and the gill cartilages causes the lower

ends of the latter to project forward in a series of

Vs into the floor of the mouth (Fig. 7). These

cartilages support the tongue proper, which at

first is only a thickening of the floor of the mouth

covered with epithelium containing the "taste"

cells. In some of the amphibians the tongue

becomes highly muscular and protrusile and by

the time we reach the lower mammals the tongue

is fundamentally the same as that of man. The

early primates have a long narrow tongue with a

well developed "under tongue" beneath it; in the

higher primates, especially the orang, chimpanzee

and gorilla, the tongue approaches the human type

but is longer in proportion to its breadth. In the

detailed number and arrangement of the papillae

123

Fig. 67. Longitudinal Section of Head in Young Gorilla (A)
and in Man (B), Showing Relation of Tongue to Surround-
ing Parts (after Klaatsch).

OUR BEST FEATURES

vallatse the orang agrees with man (Pocock,
Sonntag) .

c . , * D

Fig. 68. Longitudinal Section of Lower Jaw of Monkey (A)

and in Man (B), Showing Attachment of the Tongue Muscle

to the Back of the Jaw (after Robinson).

C. Diagram of the genioglossus muscle in pronouncing the sound
"oo." D. Diagram of the genioglossus muscle in pronouncing the
letter "T." (C, D, after Robinson.) For details, see pp. xxviii, xxix.

The muscles of the tongue are the same in the

anthropoids and man (Figs. 67, 68) but in the latter

125

OUR FACE FROM FISH TO MAN

the geniohyoglossus muscles have acquired the abil-
ity to change the precise shape and position of the
different parts of the tongue with extreme rapidity
and in conjunction with movements of other parts
of the voice-producing mechanism (Robinson).

The great size of the tongue in man and its
important function as the leading organ of speech
has doubtless partly conditioned the later stages
in the evolution of the lower jaw, especially in the
region of the chin, to the back of which the tongue
muscles are attached (Fig. 68).

Meanwhile the remaining part of the branchial
arches has given rise to the larynx with its highly
elaborate voice mechanism, to the tonsils, thyroid
and thymus glands, the last two being of vital
importance in the normal growth and differentia-
tion of the individual. Again the anti-evolutionist
can offer no alternative scientific explanation of
the fact that during the course of embryonic
development the human tongue, larynx and
adjacent structures reveal remarkably detailed
resemblances to corresponding structures of lower
vertebrates.1 The "gill-slits" in the human

1 For a clear presentation of the details see Keith, Arthur, 1921,
Human Embryology and Morphology, London, pp. 240-252.

126

OUR BEST FEATURES

embryo (Fig. 69) have been heard of by multitudes,
so that certain anti-evolutionists have tried to

Fig. 69. Human Embryo of the Third Week (prom Eidmann,
after His).

Oblique front view of the head, showing mouth, primary upper and
lower jaw buds, gill arches and gill slits.

(From Enlw. d. Zdhne . . ., Hermann Meusser, Berlin.)

offset their effect by arguing that they are not

gill-slits since gills are not present. But this

could only confuse people unfamiliar with the

evidence that each of the so-called " gill-slits " of

the human embryo of the fifth week may be

compared directly with a corresponding one in

127

OUR FACE FROM FISH TO MAN

the foetal and embryonic stages of other mammals,
of reptiles, amphibians and primitive fishes, and
that in the fishes these clefts are definitely associ-
ated with functional internal gills.

The anti-evolutionists should also be embar-
rassed by the fact that, leaving the embryonic
stages aside, and considering only adult anatomy,
the entire complex of the hyoid arch, larynx and
associated parts in man corresponds in great detail
with those of the anthropoids, differing only in the
proportional development of certain parts. From
the anthropoids down through the lower primates
the homology of every segment of the hyoid arch
and laryngeal complex can be completely estab-
lished and from thence these structures can be
traced backward step by step through the reptiles
to the lower amphibians and thence to the
elaborate branchial skeleton of the crossopt or
lobe-finned ganoids. In fact the branchial skele-
ton of vertebrates, in all its complex relations with
the muscles and nerves and in its successive stages
of development, affords convincing evidence of
the anatomical unity of the entire vertebrate
series from shark to man. The human jaws,

tongue, larynx and associated parts thus con-

128

OUR BEST FEATURES

stitute only a single manifestation of a morpho-
logical theme that has a thousand variations, but
is everywhere patently evolved from a shark-like
prototype. And in particular this region yields
most cogent evidence of man's unity of origin
with the anthropoid apes.

The salivary glands under the tongue and in
the sides of the cheek and throat afford another
example of the same kind. Huntington has shown
how even the variations in man are obviously
related to those of the higher primates.

ORIGIN AND EVOLUTION OF THE HUMAN LIPS

Let us return now to the outside of the mouth

and consider the origin and evolution of the

human lips. The mouth in the lowest existing

chordate Amphioxus (Fig. 54) is surrounded by

short stiff projections. Much the same condition

obtains in the larval lamprey (Fig. 59B). In the

adult lamprey the mouth cavity is surrounded by

a movable ring of cartilaginous plates beset with

thorn-like teeth, probably a very specialized

arrangement. In the ostracoderms (Figs. 4, 57)

of the Silurian the border of the capacious mouth

cavity was covered with small scales and plates.

129

OUR FACE FROM FISH TO MAN

In the modern sharks there is a fold of skin at the

back of the upper border of the mouth that seems

to foreshadow the maxillary or upper jaw bones

of higher fishes (Allis). Underneath this fold of

skin at the corner of the mouth are two labial

cartilages embedded in muscles which apparently

serve to draw forward the corner of the mouth

(Fig. 6). A similar fold of tooth-bearing skin

(Figs. 50, 53) in the lobe-finned ganoids, or

crossopts, gives rise to the premaxillary and

maxillary bones, which have every appearance of

being homologous with the bones that bear the

same name in the earliest amphibians, and from

thence these two bones can be followed through

the mammal-like reptiles to the earliest mammals,

thence through the ascending grades of primates

to man. In the earlier crossopts these bones were

covered with enamel and lay right on the surface

but in the more advanced crossopts the ganoine

layer has disappeared and the outer surface of

the bone is rough, indicating that it was covered

with a thick tough skin. The dentary bone of

the lower jaw was likewise covered.

In the early amphibians and reptiles the pre-

maxilla, maxilla and dentary were likewise rough-

130

OUR BEST FEATURES

ened for the attachment of the outer layers of the
skin, of which they themselves formed the deeper
layers. In some of the recent reptiles there is a
small muscle at the corners of the mouth but the
lips are not fleshy and the tough facial mask is not
far below the surface. Probably the same condi-
tions obtained in the entire series of mammal-like
reptiles.

In the most archaic mammal living today, the
Duckbill Platypus of Australia, the mouth is
surrounded by a duck-like bill consisting of leathery
skin well supplied with sense organs. Very
possibly this condition is a specialized remnant
of the tough skin that covered the mouth of the
mammal-like reptiles. In the Spiny Anteater
(Echidna) of Australia (Fig. 23C), the nearest
living relative of Ornithorhynchus, the lips, although
peculiarly specialized in connection with the ant-
catching, protrusile tongue, approach the normal
mammalian condition in so far as they are supplied
with muscles that are innervated by the seventh
or facial nerve and are covered with hair rather
than scales.

Here we arrive at the most distinctive feature of

the lips of mammals, in which the bony mask

131

OUR FACE FROM FISH TO MAN

inherited from the primitive crossopts lies deeply
covered by a mobile fleshy curtain. Doubtless
the evolution of true lips was a part of the general
transformation of reptiles with unstable body
temperature and low grade metabolism, into
mammals living at high pressure.

In an earlier chapter (pages 43, 44) it has been
mentioned that the facial muscles of mammals
represent a forward extension of a thin layer of
muscle covering the neck of lower vertebrates and
that when this muscle migrated forward beneath
the skin it dragged its own nerve with it, which
was subdivided into smaller branches as the
muscle itself was differentiated into the facial
muscles of the ears, eyes, nose and lips (Figs. 23,
24). The history of this invasion is now being
traced in convincing detail by Huber. The inva-
sion was facilitated by the fact that in the early
stages of development (Figs. 65A, 69) the region
of the mouth and lips arises quite close to the
original territory of the facial nerve, which was
on the side of the neck, so that forks of the parent
mass in the neck could easily spread to the lips
and forehead.

The researches of Ruge, Huber, Sonntag and

132

Fig. 70. Old Chimpanzee, Showing Extra-
ordinary Protrusion of the Lips in
Anthropoids.

(From J. A. Allen, from a photograph
by Herbert Lang.)

OUR BEST FEATURES

others have shown that the anthropoids (as usual)
are man's nearest living relatives in the anatomy
of the facial muscles. The ability to move the
ears is already reduced in the anthropoids but
some men can still make a creditable showing of
activity in these souvenirs of man's earlier mam-
malian ancestors.

In the lower primates the opposite upper lips,
ljke those of carnivorous mammals, depend slightly
at the sides and are barely, if at all, joined in
front, but in the anthropoid apes and man the
median flap of the foetus, forming the philtrum of
the lip in adult man, becomes very broad, so that
the opposite halves of the orbicularis oris muscle
become broadly continuous.

Thus the anthropoids acquired highly protrusile

lips, useful in sucking up water and the juices of

fruit (Fig. 70). Man has inherited from the

primitive anthropoids the ability to draw back his

lips in anger, to open them in a laugh, or again, to

protrude them into a funnel and so to confer kisses

on the objects of his affection. How much dour

literature, ancient and modern, might be lightened

by this thought!

All these muscles of the mouth and cheeks as

133

OUR FACE FROM FISH TO MAN

well as the muscles of swallowing were naturally
of vital importance to the newborn mammal,
enabling it to pump the mother's milk into its
swelling cheeks. But how long it took mankind to
realize the deep significance of the fact that even
babies of bluest blood share this birthright with
the beasts of the field.

LATER STAGES IN THE HISTORY OF THE TEETH

Thanks to the advertisers of tooth pastes all
America knows the practical importance of beauti-
ful teeth. But few indeed share the secret as to
how we obtained these dazzling objects of charm,
and fewer still ever give a thought to the humble
creatures who slowly shaped them to our use.
It is surprising that even today, after hundreds of
millions of years' advancement beyond our shark-
like ancestors, each human being, during the
embryonic development of his teeth, starts at a
shark-like stage (Fig. 71 A). For at first the area
of embryonic skin that is destined to give rise to
the teeth lies on the surface of the mouth cavity,
then it sinks down like a pouch (Fig. 71B), the
bottom of the pouch is pushed upward (Fig. 71 C)

to form a pulp cavity and thus the germ of the

134

OUR BEST FEATURES

human tooth becomes essentially like the germ
of the shark's tooth. However, in order to defend

uppcrjaur

toothpouch,

tongue-

'-* J mouthcarity ^

lowerjaur

toolh-oparma
skin,

tongue

toothpouch

;>.v.'4_^.'

tourer

Fig. 71. Three Embryonic Stages in the Development of Human
Teeth (A, B, from Eidman after Ahrens; C, after Corning).

(A, B, from Entw. d. Zahne . . ., Hermann Meusser, Berlin; C, from Lehrb. d.
Entw. des Menschen, J. F. Bergmann.)

For details, see p. xxix.

the validity of these comparisons it is essential to

note that we are not leaping at once from shark

135

OUR FACE FROM FISH TO MAN

to man in the reckless manner of some of the
older comparative anatomists, but that the same
general process of tooth development may be
traced in many successive grades in the ascent
from fish to man.

Meanwhile (Fig. 71C) Meckel's cartilage, the
descendant of the primary lower jaw of the shark,
lies entirely free from the future dentary or lower
jaw bone, which will later surround both the
Meckel's cartilage and the developing tooth-germ,
as in all the vertebrates above the shark.

In the earlier creatures that lie in or near the
line of ascent to man the teeth were of the dog-
tooth or canine type (Fig. 50). Some of the front
teeth of man, especially the cuspids or canines,
remain single-cusped to this day as souvenirs of
our remote carnivorous ancestors; but the central
incisors often exhibit a tendency to develop little
cusps, mammillae or subdivisions, along the flat-
tened cutting edge of the crown (Fig. 72). The
frequent presence of these mammillae on the edges
of the central incisors has sometimes been cited as
evidence of a " triconodont " stage in the evolution
of human teeth, in disregard of the fact that not

even the extinct triconodont mammals of the

136

OUR BEST FEATURES

Fig. 72. Central Incisors of Gorilla (A, E) and Man (B, C,

D, F). Enlarged. (B, after Weinert, C. F, after Virchow;

D, after Hrdlicka; G, from Hrdlicka,

AFTER ZUCKERKANDL.)

For details, see pp. xxix, xxx.

Triassic age themselves had " triconodont " incisors

but only triconodont molars. In whatever way

this tendency to subdivide the central incisor

137

OUR FACE FROM FISH TO MAN

edges may have arisen, man shares it with many
other mammals, especially with his relatives the
anthropoid apes, whose central incisor crowns
approach the human type. Remane (1921, Fig.
21E) has shown that in certain chimpanzees even
the outer rim of the central upper incisor is vertical
as in man.

Hrdlicka has noted that on the rear surface of
the central upper incisors of certain anthropoids
and monkeys one finds the "rim and ridge"
formation (Fig. 72) of many human incisors.

In the upper central incisors of recent Mon-
golians and many Indians the rims along the
sides of the crown fold around toward the rear
and the "shovel-shaped" incisor is developed.
This arrangement was already foreshadowed in
certain gorillas and is almost fully attained among
the extinct Neanderthals of the Krapina race; it
has also recently been discovered in a fossil human
tooth from the Pleistocene of China. In its
extreme form the shovel-shaped incisor represents
a distinct specialization beyond that attained in
the anthropoids. Dr. J. Leon Williams has
observed among all races of mankind the presence

of three types of central upper incisors (Fig. 73).

138

OUR BEST FEATURES

In the first type the inner and outer borders of the
crown as seen from in front tend to be straight
and vertical; in the second type the opposite
borders diverge sharply toward the lower end of
the crown; and in the third the outer border has a

Fig. 73. The Three Types of Central Upper Incisors (after
J. Leon Williams).

Lower row, first type; middle row, second type; upper row, third type.

marked double curve. Exactly these same three

variants he found also in all the existing species of

anthropoid apes and he rightly considers that this

fact, taken in conjunction with hundreds of other

items of similar purport, affords decisive evidence

of close kinship between man and anthropoids.

The upper lateral incisors in anthropoids (Fig.

74) as a rule are more primitive in retaining the

139

Fig. 74. Palatal Arches of
Anthropoids and Men: A.
Gibbon, Female; B. Gorilla,
Male; C. Chimpanzee, Fe-
male; D. Orang, Female; E.
Neanderthal Man; F. Mod-
ern White Man, Composite.

(A, B, C, F, from Selenka, after
Rose; D, after Hrdlicka; E, from
Weinert, after Dieck.)

140

OUR BEST FEATURES

bluntly pointed tips, but Remane (1921, page 102)

figures a certain chimpanzee in which the tip of the

lateral upper incisor is submerged in a transverse

incisal edge and even the outer rim is vertically

developed, so that the crown as a whole is clearly

approaching the human type.

The great outstanding difference between the

dentition of man and that of his anthropoid

cousins lies in the fact that in man the canine

teeth, even in the milk set (Fig. 76) are much

reduced in size, with rounded crowns and obtuse

tips that project but little above the level of the

adjacent teeth, while in the anthropoids, especially

the males, the canines form large sharp- tipped

tusks. If, however, the fossil lower jaw found at

Piltdown, England (Fig. 45 C), belongs with the

human Piltdown skull, as nearly all authorities

now believe, it affords a clear case of an ape-like

canine belonging in a human jaw; only it should

be noted that the Piltdown canine is much more

like the lower canines of certain female gorillas,

which have not attained the tusk-like stature of

male canines. The human canines may indeed

be most reasonably regarded as reduced and

" inf antilized " or "feminized" derivatives of a

141

OUR FACE FROM FISH TO MAN

primitive anthropoid type and the process of
reduction and infantilization may well have taken
place during the millions of years of the Lower
Pliocene epoch, at a period when the fossil record
of human remains so far discovered is still blank.

The great mass of collateral evidence for the
derivation of man from primitive anthropoids with
well developed but not greatly enlarged canines,
has been reviewed lately with great thoroughness
by Remane, who finds no justification for the
view that man has avoided the primitive anthro-
poid stage and has been derived from wholly
unknown forms with the canine tips not projecting
much beyond the level of the premolars.

When the skull of a chimpanzee (Fig. 35F) and

the skull of a high type of man (Fig. 43D) are

viewed from above, the ape is seen to differ widely

from man in the marked projection of his muzzle.

This projection is less in female anthropoids with

smaller teeth and still less in early fcetal anthropoid

stages before the tooth-germs are formed. On the

other hand, savage types of man with very large

teeth have a correspondingly prominent muzzle,

especially if the molar and premolar teeth have

large fore-and-aft diameters, as in the fossil

142

OUR BEST FEATURES

Talgai, Australia, skull (Fig. 42E), which has a
strongly protruding muzzle. Again, the Piltdown
lower jaw (Fig. 45C) with its "simian shelf" in
front, its female anthropoid canine and its ape-
like molar teeth (Fig. 41 A), must indubitably have
had a muzzle approaching that of an immature
female gorilla. By the time we reach the Heidel-
berg and Neanderthal fossil men, however, the
canines had become reduced to the level of the
cheek teeth, the incisors and premolars were
reduced in size and the lower molars were relatively
wider than in the anthropoids; hence Professor
McGregor's very thoroughly studied restorations
show these men with only moderately developed
muzzles and human lips.

The reduction of all the front teeth in man is
foreshadowed in the foetal stages in which the
tooth-germs are smaller than those of apes;
consequently the fcetal muzzle is likewise smaller
than that of fcetal apes of corresponding stages.

The reduction in size of all the teeth, especially

the canines, has been an important factor in

shortening the palatal arch (Fig. 74) from the

long P| -shaped type of anthropoids, with a wide

space between the canines, to the short human

143

OUR FACE FROM FISH TO MAN

form of palate with narrow space between the
canines. In the lower jaw the diminution of the
lower canines and the backward retreat of the
incisors finally brings the canines almost to the

Fig. 75. Lower Front Premolars of Fossil Anthropoids
(A, B, C) and Man (D, E).

(A, B, after Gregory and Hellman; C, after Pilgrim; D, after Virchow;
E, from Selenka, after Rose.) For details, see p. xxx.

front of the jaw and into functional alignment with
the incisors.

The upper premolars or bicuspids of man, which
in the adult dentition are two in number on each
side of both the upper and lower jaws, find their
nearest relatives in the bicuspid upper and lower
premolars of the anthropoid apes (Fig. 74).

The front lower premolars of the anthropoids

show a wide range of forms, from types with a more

compressed baboon-like crown to the almost human

premolars of the extinct Sivapithecus (Fig. 75 C)

144

OUR BEST FEATURES

and of certain modern chimpanzees. Remane
records the fact that in certain human jaws the
front lower premolar retains clear vestiges of the
asymmetrical form of the outer surface of the
crown, a condition that is far more accentuated in
the typical anthropoids and is there associated
with the large size and tusk-like form of the upper
canines.

Neither the upper nor the lower molars of man
show much resemblance to those of the cynodonts
or pro-mammals of the far-off Triassic age (Fig.
771) ; yet we owe to such lowly forbears the initial
phases of the process by which the simple dog-
tooth crowns of the cheek teeth began to subdivide
and give rise to the accessory tips or cusps that
are so characteristic of the cheek teeth of mammals.

Anti-evolutionists ask us to believe that even
the hairs of our head are numbered, but we affirm
only that our teeth are numbered: twenty in the
milk set and thirty-two in the permanent sets of
normal individuals ; and that the same numbers oc-
cur in the anthropoid apes ; that typical represent-
atives alike of mankind and of the apes, have in
the permanent dentition two incisors, one canine,

two premolars, three molars, on either side in both

145

OUR FACE FROM FISH TO MAN

the upper and lower jaws; and in the milk set, two
incisors, one canine and two milk molars on either
side above and below (Fig. 76).

The history of the human upper and lower
premolar and molar teeth (Figs. 77, 78) has been

two milk incisors
upper

lower
canine

turotnilKmotars B
lower

Fig. 76. Milk Teeth of Man (A) and Gorilla (B). (Both from
Selenka, after Robe.)

discussed at length by myself in the work on the
Origin and Evolution of the Human Dentition and
other papers and by Gregory and Hellman in
our work on The Dentition of Dryopithecus and
the Origin of Man. We have shown that not-
withstanding the present profound differences in
habits between man and the anthropoid apes, the
lower molar teeth, especially of more primitive

and more ancient races of man, retain the most

146

147

h 53
. 'S d

<! ^ 0>J2

* &5.S '-

^ d o
65 "IT wS

S 4) U O,

EH S|^

r" "if ;3_,

2 « 3
2 -p n

i — i ^ OJ)

> & u

148

OUR BEST FEATURES

indubitable marks of anthropoid kinship and

derivation; the lower molar crowns displaying

many intermediate stages from an almost perfect

"Dryopithecus pattern" (Fig. 80C) with five

main cusps and a complex, definite system of

grooves and depressions, to a "cruciform," four-

cusped form in which the Dryopithecus pattern is

largely obliterated (Fig. 80F).

Similarly the upper molar crowns of the fossil

Neanderthal skull known as "Le Moustier"

(Fig. 78IX) may be compared cusp for cusp and

ridge for ridge with those of such fossil anthropoids

as Dryopithecus rhenanus of Europe and Sivapi-

thecus of India, both of which even possess the

peculiar depressions known as the fovea anterior

and fovea posterior, which are characteristic of

primitive human upper molars. Here again, as

in the case of the lower molars, it is only the more

primitive members of the human race that retain

such indubitable traces of anthropoid kinship, the

conditions of civilization tending to reduce the

vigorous upper molar pattern of the primitives

to an enfeebled type with less robust cusps and

less salient angles (Fig. 78X).

Similarly the entire set of milk teeth of man

149

m.3.

m.2.

TTL.1.

77?

Fig. 79. The Dryopithecus Pattern in the Lower Molar Teeth
of Fossil (A, B, C) and Recent (D, E, F) Anthropoids.

For details, see p. xxxii.

150

m.3.

m.2.

m.i

Fig. 80. Progressive Reduction and Loss of the Dryopithecus

Pattern in the Lower Molars of Fossil (A, B, C)

and Recent (D, E, F) Men.

For details, see pp. xxxii, xxxiii.
151

OUR FACE FROM FISH TO MAN

must be regarded from a scientific viewpoint as
derived by a few easily understandable modifica-
tions, from the type exemplified in the young of
recent anthropoids (Fig. 76).

Against all this mass of evidence for man's
evolution from a primitive anthropoid stock the
modern schoolmen can only quibble that the
corresponding parts of man and ape are "equi-
vocable" but not "homologous."

CONCLUSIONS

Perhaps the most important and basic conclusion

concerning the early history of the mouth and jaws

in the remote ancestors and predecessors of man is,

first, that however the mouth and jaws may have

arisen in the first place, their subsequent history,

from the grade of organization represented by the

shark, may be traced through to man in its broad

outlines with the greatest security; secondly, that

whatever may have been the food habits of the

invertebrate ancestors of the vertebrates, it is

extremely probable that from the shark grade

onward to the early mammalian ancestors of man,

the mouth and jaws were adapted for the capture

and disposal of sizable living prey and not for

152

OUR BEST FEATURES

the manipulation of any less nutritious form of
food.

The amelioration of our features we owe not so
much to the savage, furry little beasts that first
bore the name of mammals, nor even to the earlier
primates, who despite their large eyes and large
brains still retained a fox-like snout and long jaws ;
but chiefly to the gentle pro-anthropoids who first
took to a diet of fruit and buds and so acquired
many modifications of the lips, jaws and dentition,
which they transmitted to the earlier and less
progressive races of men.

How much arrogance, deceit and wickedness would
have been spared the world, if men had realized that
even the most imposing human faces are but made-
over fish traps, concealed behind a smiling mask but
still set with sharp teeth inherited from ferocious pre-
mammalian forbears.

History of The Nose

Why do all men, anti-Darwinians included, have

noses ? Why does the human nose, both externally

and internally, have precisely the same parts, only

differently proportioned, as the noses of the gorilla

and the chimpanzee? Why are man and ape,

153

OUR FACE FROM FISH TO MAN

in this feature as in thousands of others, created so
nearly in the same image? "Parallelism" say the
anti-Darwinians; but physiology, comparative
anatomy and allied sciences answer, "Blood
kinship."

The story of the early evolution of the human
nose would be strong reading for the delicate
stomachs of our Mid- Victorian lady relatives.
But in these Neo-Elizabethan days we will not
shudder unduly at the thought that noses, at least
of the vertebrate type, were first created in order
to lead our shark-like ancestors straight to the
feast — some nameless horror wallowing in the
uneasy tide and alive with the writhing creatures
that consumed it. Even to this day, odors cannot
reach us except in water vapor.

The shark's smelling apparatus is comparatively

simple — an extended surface of membrane sensitive

to olfactory stimuli, folded into a rosette and

packed neatly into the olfactory capsule, one on

each side of the head. A small opening, the nostril,

admits the water to be tested, and a groove, the

oronasal groove of primitive sharks (Fig. 66 A),

connects the nose with the mouth cavity. In the

embryo shark and embryo mammal the nasal sac

154

OUR BEST FEATURES

begins as an out -pushing of the mouth cavity, of
which it thus appears to be only a specialized
outgrowth for the detection and testing of food.

olfactory

otic-
capsule

spiracle

Fig. 81. Dissection of Head of Shake, Seen from Above, to

Show Relations of Olfactory Capsules to Brain, Eyes

and Internal Ears (Modified from Marshall and Hurst).

The most essential parts of the nose are the

olfactory sense organs and the olfactory nerve.

The fibers of the latter are spread all over the

olfactory membrane, from which, being collected

into two great nerve cables (Fig. 81), they pass

155

OUR FACE FROM FISH TO MAN

backward into the forebrain, of which indeed they
form the dominant part. If favorable signals are
transmitted by the smelling nerves, the eyes turn
toward the source of the odor and by means of the
locomotor machinery the whole "ship" is steered
in the right direction. The two olfactory capsules,
rather widely separated from each other on either
side of the head, not only double the chance of
picking up a trail of olfactory value, but doubtless
also serve as directional organs. The bilateral
arrangement of the other sense organs may have
a similar significance.

The resemblances of the shark nose to the human
nose are fundamental and the subsequent changes
in this organ are relatively not great. The ultimate
mystery with regard to all the sense organs of
vertebrates is decidedly not what are the broad
stages of their evolution from fish to man, but
what physical and chemical forces acting upon the
primitive vertebrate skin caused one set of epi-
thelial cells to become sensitive to olfactory
stimulations, another set to respond to light, others
to physical vibrations of different rates, and still
others to be deaf and blind to all other stimuli

except those coming from within the organism;

156

OUR BEST FEATURES

and what now causes other cells of the same
primary outer layer to become a line of olfactory
nerve cells, attached to the sense organ and arising
from a nucleus in the central nervous system.
Experimental embryology and physiology of the
future may reveal some of the chemical changes
involved, as the generalized ectoderm cell differ-
entiates into the specialized one capable of only
one class of reactions; but this will only widen our
knowledge of the bewildering complexity of the
single fertilized egg cell, which divides and sub-
divides so as to give rise to the olfactory organs as
well as to all other parts of the body.

Meanwhile, as stated above, the main tran-
sitional stages in the evolution of the nose from
fish to man are fairly well understood, and are well
described in Keith's Morphology and Embryology.
First the olfactory sac becomes folded up, and in
sharks a groove (Fig. 66A) extends downward
toward the corner of the mouth. Second, in the
lung-fishes this lower extension of the sac has
worked its way inside the mouth and there are
thus two openings, a nostril on the outside and
an internal narial opening in the roof of the mouth.

Third, both in the air-breathing fishes and the

157

OUR FACE FROM FISH TO MAN

amphibians air may either be gulped in through
the mouth or sucked in through the nose, which
thus functions in breathing as well as in smelling.

By the time we reach the mammal-like reptiles
of the Triassic of South Africa (Fig. 53VI) we find
the paired olfactory capsules greatly elongated in a
fore-and-aft direction, and in the highest members
of this series, as shown by iron-stone casts of the
interior of the nasal chamber, the median bony
partition now supported scroll-like outgrowths
like the delicate turbinate bones of mammals
(Watson). The delicate olfactory membrane thus
spread out on these scrolls, which in many mam-
mals become complicated with secondary scrolls,
thus secures a wide surface for testing the odors
of the air drawn in.

In the living amphibians, reptiles and more
primitive mammals there is also a pair of small
cartilaginous scrolls near the bottom of the
median cartilaginous partition, which contains a
folded pocket of the olfactory membrane; from this
pocket a very fine tube leads downward, opening
into the cavity of the mouth. This whole arrange-
ment is called Jacobson's organ. Primitively

Jacobson's organ seems to have served for the

158

OUR BEST FEATURES

testing by the olfactory membrane of the contents
of the mouth, while the main portion of the olfac-
tory membrane served to test the inspired air in
the main chamber. In the marsupials and other
lowly mammals Jacobson's organ is comparatively
well developed but in the higher primates and
especially in man it is either absent in the adult

... septal
^cartilage

^JacobsonS'
organ

cartilage of nose

Jacobson's
organ

■Jacobson's
cartilage

-palatab
process

Fig. 82. Jacobson's Organ in the Human Foetus.
(After Corning.)
(From Lehrb. d. Entw. des Menschen, J. F. Bergmann.)
For details, see p. xxxiii.

stage or it exists in a vestigial and, so far as known,

a useless condition. It is present, however, in the

early foetal stages of man (Fig. 82), degenerating

later. Here then is another "poser" for anti-

evolutionists. Is the foetal human Jacobson's

organ made after a divine prototype? And is the

same true of the vestigial Jacobson's organ of the

Old World monkey? Or have both man and

monkey received this now vestigial or foetal struc-

159

OUR FACE FROM FISH TO MAN

ture as part of their heritage from far earlier
mammals in which it was more fully developed?

fronted 6inus

'uppermeatus

middle "
lower '

frontalsmus
uppermeatus

A spkenoidmus

Fig. 83. Longitudinal Section of the Skull in Man (B)
(after Cunningham) and Chimpanzee (A).

A similar dilemma might politely be offered to

anti-evolutionists with regard to the whole anatomy

160

OUR BEST FEATURES

of the olfactory chamber. Why is it that man
agrees with the Old World monkeys and anthropoid
apes in the numbers and arrangement both of the
turbinate scrolls that arise from the median
partition or septum and of those that spring from
the inner wall of the upper jaw bone? In man

Fig. 84. Broad Forwardly-directed Nose of Human Fosttjs (A)
(after Kollmann) and Gorilla Fcetus (B) (from

SCHULTZ, AFTER DENIKER).

these delicate bony scrolls, deeply buried in

mucous membrane, are arranged in such a way

that three air passages, the upper, middle and

lower meati, pass between the scrolls and allow

the air to pass downward and backward to and

from the pharynx. In the Old World monkeys

and anthropoid apes the same passages are present

as in man, but in the chimpanzee and the gorilla

the resemblance to man is even more striking,

since the air cavities or sinuses in the frontal,

161

OUR FACE FROM FISH TO MAN

ethmoid and sphenoid bones have similar tubular
connections with the nasal meati (Keith).

Nor should the anti-evolutionist be any less
embarrassed by the history of the embryonic
development of his own nose in comparison with
that of other animals. For, broadly speaking,
the human nose passes through an early stage in
which the olfactory capsule is undeniably like that
of a fish (Fig. 65) ; then the lower end of the capsule
is prolonged downward in a tube which opens into
the roof of the mouth; at this stage the morphology
of this region is substantially like that of an
amphibian or of a reptile; then horizontal plates
(Fig. 66D) grow out from the upper jaw to form
a secondary bony palate, so that the mammalian
grade is reached in which the inspired air is
delivered into the pharynx back of the palate.

Meanwhile the membranous Eustachian tube
has sent off bubble-like outgrowths (Fig. 85),
which invade the frontal, ethmoid, sphenoid and
superior maxillary bones, forming in them the
complex system of sinuses and antra which in its
entirety is peculiar to man and the higher anthro-
poid apes (Keith).

With regard to the external nose, neither the

162

OUR BEST FEATURES

comparative anatomy nor the embryonic develop-
ment of this region give the slightest support to
those who stress the isolation of man. On the
contrary, they show quite conclusively that man
and apes are merely the divergently modified
derivatives of a common pro-anthropoid stock and

«g&A uwertfmafe

k /pituitaryfossa.

sinus

******* '. "'^^^s^^M'A Sphenoid

lower * ■ "M&T v^ ,£?*»feS^wX--'*' sinus

Fig. 85. Connections of the Fkontal, Ethmoid and Sphenoid
Sinuses with the Nasal Meati (after Keith).

that with regard to this region civilized man has

become much further modified away from the

primitive ancestral condition than either the gorilla

or the chimpanzee.

In earlier human stages of development (Fig.

86) the nostrils are widely separated, almost as in

the South American monkeys. Later (Fig. 86E)

the opposite halves of the nose grow together.

At this stage the nose is very wide in proportion

163

OUR FACE FROM FISH TO MAN

to its height and as a whole is essentially indentical
(Fig. 84B) with that of foetal chimpanzees and
gorillas. This fact, together with a multitude of
similar ones, establishes the relatively close rela-
tionship between man and the existing anthropoids ;
it also indicates that in the shape of its nose the
common ancestor of man and the anthropoids was
far more like a gorilla than like a white man.

According to Professor Schultz, even unborn
foetuses show wide differences in the form of the
nose, but in general, babies have wide short noses
with very low bridges. In the negro pygmy
represented in Fig. 89A the nose has remained in
a low stage of foetal development (cf. Fig. 86D).
In the Mongolian race the infantile form of nose
tends to be retained in the adults. How then
does one baby grow up to have the famous figure-6
Jewish nose, another the V-shaped Alpine nose?
How did that pretty British girl acquire a nose
which has just the suspicion of an upturn at the
tip? Why do exceedingly tall men have very
long noses? Why do fat men often have inade-
quate juvenile noses? Of course it seems like a
truism to say that in thin sharp noses the vertical

components of growth of the nasal septum have

164

OUR BEST FEATURES

far outstripped the transverse components of the
nose as a whole; yet such no doubt are the most

foredrain

midbrain

globular,
process

nasalfield
nostril

' maxilfa'rj/ process
"upperjaur&zfp

jmandi6u2arprocess
'tourer jaw & up

forebrain
nasal-field

side of nose
jiostril

upperjaw
lourerjaur

] \ gill arches

qlobular
process

nasatfield

MpperjawSf lip

lawerjaur
slip

Fig. 86. Embryonic Development of the Face in Man. (From
eldmann, a, b, after hls, c, after rabl, d, e, after retzius).

(From Entw. d. Zahne . . ., Hermann Meusser, Berlin.)
For details, see p. xxxiv.

important factors in producing the excessively

different extremes shown in Fig. 89.

165

OUR FACE FROM FISH TO MAN

Let us consider further then the general course
of embryonic development of the nose. In all
mammals, including man and the anthropoid apes,
the face in front of the eyes is formed during
individual development (Fig. 86) by the growing

Masai,
field

iphillrum M- -v ^|

[Mproc.

\ plus

\ nasal field,

maxillary
process

znandiiular
process

\-~ i gillarches

Fig. 87. Foetal (A) and Adult (B) Development of the Face in

Man. (A, from Eidman, after Retzius;

B, Modified from Keith).

(A, from Enlw. d. Zahne . . ., Hermann Meusser, Berlin.)

For details, see p. xxxiv.

together in the mid-line of a system of five flaps or

rounded processes, four of which represent the

opposite halves of the cheeks and upper and lower

lips and jaws, while the fifth, a median area (the

nasal field) forms the middle of the philtrum of

the upper lip and the middle part of the nose.

The sides of the nose are formed from the growing

together in the mid-line of the nasal field and the

166

OUR BEST FEATURES

enlarged olfactory capsules. The lateral or alar
cartilages of the external nose represent a forward
growth of the margins of the olfactory capsules.

According to Broom, the median cartilage or
septum of the nose appears to have been derived
originally from a forward prolongation of the base
of the skull (presphenoid) and in the mammal-like
reptiles, marsupials and some other orders of
mammals it is still formed that way; but in man
and other primates the forepart of the septum
acquires a separate center of ossification and
becomes the mesethmoid bone.

Schultz has shown (Fig. 88) that as develop-
ment proceeds the middle cartilage (septum)
grows forward and downward faster in man than
in the anthropoids and faster in the white race
than in the negro race; thus in the latter the
everted lips and more protruding front teeth are
associated with a less deep median septum and a
lesser downgrowth of the nasal tip. In adults of
all races the nose gets longer, narrower at the base
and more raised at the bridge. Thus babies and
young children have relatively shorter, less prom-
inent noses than adults (Fig. 87).

The median partition (septum) that supports

167

OUR FACE FROM FISH TO MAN

the tip of the nose is tied to the bone above the
incisor teeth. If then the front upper jaw bone

Fig. 88. Nasal Profiles and Related Parts in Man: A, Negro
Child; B, Negro Adult; C, White Child; D, White Adult.
(All after Schultz.)
For details, see pp. xxxiv, xxxv.

(premaxilla) has a feeble growth, it will not grow
far forward (as it does in the anthropoids) and

hence the anchorage of the median septum will be

168

OUR BEST FEATURES

relatively far back. This will tend both to increase
the prominence of the nose as a whole and to give
a downward inclination to the tip. In the typical
Dinaric or Hittite nose (Fig. 89C) the resultants of
all the horizontal, forward components and of all
the downward components are very conspicuous.

If the transverse growth components of the palate
are relatively weak, the bony palate may buckle up
and the median septum may either bend on one side,
producing a partial closure of the nasal passage, or
possibly it may be displaced upward, producing a
high-ridged or humped nose. If the bridge and the
lower end of the nose as well as the median partition
are all retarded in their growth, as in achondroplastic
dwarfs, a marked repousse or pug nose, with almost
upturned tip, will result (see below, page 230) . In
the orang the median partition itself seems to lag
in growth, while the orbits are crowded together
and the nasal bones are extremely reduced.

The transverse components of growth are
obviously in the ascendant in extremely wide
noses with broad nostrils and low bridges, as in
Australian and Tasmanian aborigines, Papuans,
Melanesians, negritos and negros. Such condi-
tions are apt to be associated with prognathous

169

OUR FACE FROM FISH TO MAN

jaws and large teeth (Fig. 89D). The reduction
in size of the tooth row as a whole seems to have
permitted or favored the vertical and forward
growth of the nose, while the opposite tendency
culminates in the gorilla, which has enormous teeth
and an extremely broad nose. Doubtless other fac-
tors complicate the results, for instance, the lateral
cartilages or alse of the nose must in themselves have
varying growth power, very feeble in the orang,
vigorous in the gorilla, still more so in man.

The form of the nose bridge is likewise condi-
tioned by many factors. The greater the volume
of the brain in the foetus, the sharper will be the
bending of the brain upon itself, and the further
forward will be pushed the greater wings of the
sphenoid bone and the temporal region of the
skull. All this has a tendency to push the face
forward, especially the lateral angles of it, so that
in extremely wide-headed forms the cheeks often
protrude and the outer corners of the eye-orbits
are far forward. This produces the Mongolian
type of broad flat face, often with a wide space
between the orbits and a low flat bridge and
protruding eyes. The varying shape of the lower

end of Mongolian noses is perhaps correlated with

170

Fig. 89. Extremes of Nose Form in Man: (A) African Pygmy;

(B) Tyrolese; (C) Armenian; (D) South African Bushman. (A, B,

from Martin, after Czekanowski, D, after Schultz; C, after

von Luschan).

(A, B, D, from Lehrbtich der Anthropologic. Gustav Fischer).

For details see p. xxxv.

OUR BEST FEATURES

other factors, such as the width of the palate.

Among other possible factors affecting the shape
of the nose is the extent of upward growth of the
frontal process of the superior maxillary bone (Fig.
50) . This process is a small prong or fork, one on
each side of the head, in contact with the frontal
above and supporting the nasal bone. An increase
in size of this process would tend to elevate the
bridge of the nose. Similarly a down growth of the
whole maxillary bone, as in acromegalic persons,
produces a marked vertical lengthening of the
nose.

Here we touch upon the question, what causes
all these individual growth differences? The
cretins and achondroplastic dwarfs, which have
broad pug noses, have deficient thyroid glands,
and the acromegalics with very long noses and
protruding chins have diseased pituitary glands.
For these and other reasons many authors are
inclined to look upon the "hormones" that are
thrown into the blood stream by the different en-
docrine glands as stimulators of differential growth
or development; but it is also recognized that each
growing part has its normal range of response or

receptivity to the appropriate hormones. Con-

171

OUR FACE FROM FISH TO MAN

sequently the mechanism of the development of
any given part may be threefold: that is, it may
involve first, its own inherent and probably heredi-
tary growth power; secondly, the quality or amount
of specific hormones produced by the endocrine
glands; thirdly, the degree of receptivity of each
part to the stimulation of the hormones.

The common saying, "As plain as the nose on
one's face" is an unscientific recognition of the
dominance of the nose in the human physiognomy.
The studies of Schultz on the development and
growth of the human nose, and of Stockard on the
principles and factors of development and growth
in general give us a slight hint of the complexity
of the factors that mould the individual nose.
Except in the case of identical twins no two
persons will carry the same hereditary factors
affecting nose form, while even in the case of
identical twins the nutritional factors can hardly
be exactly the same, especially after birth. The
resulting diversity in nose form is as bewildering
as the diversity in patterns of a kaleidoscope and,
at least to some extent, is conditioned by the same
law of chance associations of hereditary and

environmental influences.

172

Fig. 90. Extremes in Face Form and Color: (A) Hottentot Woman

(from Martin, after Poech, Lehrbuch der Anthropologic, Gustav

Fischer); (B) Nordic Swede (from Lttndborg and Runn-

strom, The Swedish Nation, H. W. Tullberg.).

OUR BEST FEATURES

Optical Photography and its Results

the human eyes as instruments of precision

All sense organs are instruments of precision
that register varying intensities of the pulsing
streams of energy to which they are exposed.
The paired eyes of man, together with their con-
nections in the central nervous system, register
even slight changes in the intensity of light, they
respond to a wide range of its wave length, and
hence discriminate colors, and they are extremely
sensitive to the movement of images across the
retina. Through their binocular adjustments they
record extension, relative distances, and move-
ments in a three-dimensional field, and by their
biconjugate movements they can find a moving
image and keep it in focus within wide limits.

THE EYES OF INVERTEBRATES

The anatomy and physiology of the eyes of

invertebrates and vertebrates are the subjects of

an enormous literature, which has been admirably

summarized by L. Plate in his Allgemeine

Zoologie und Abstammungslehre, Zweiter Teil,

Jena, 1924, wherein are set forth more fully most

173

OUR FACE FROM FISH TO MAN

of the facts cited in the present chapter.1 The
lower forms of animals exhibit a wide diversity of
organs sensitive to light, in various stages of
complexity. Too long exposure to the ultra-
violet rays has an injurious or even fatal effect on
many organisms, such as bacteria, infusoria,
hydroids, rotifers, nematodes, etc. (Plate, 1924,
p. 386), which hence shrivel up or shrink away
from these rays, while as everyone knows, plants
turn toward the sunlight and some animals love to
bask in the sun. Hence in view of the importance
of light to the organism in one way or another, it
is not surprising that even in very simple one-
celled forms such as certain protista there should
be clear granules, like lenses, sometimes backed by
dense pigment, which may in some way act as
rudimentary eyes and contribute to the organism's
different reactions to light of different intensities
(Plate, 1924, pp. 424-427). At any rate, when
we come to certain of the jelly fishes we find
undoubted eyes or ocelli in the outer layer or

1 Professor Plate (in litteris) calls attention to the fact that, con-
sidering the enormous range of electric waves (from almost zero to
hundreds of kilometers), it is remarkable that the whole gamut of
human sensation of light, color, form and movement, with all their
derived pleasures, is caused by so relatively narrow a range of electric
waves. " How different our picture of the world would be," he
writes, " if we had more such regions! "

174

OUR BEST FEATURES

ectoderm of the cup-shaped body. In some cases
(Fig. 91 A) each ocellus consists only of a slightly
raised patch of larger pigment-bearing epithelial
cells alternating with smaller "light cells." The
patch grades into the ordinary epithelial cells
around it. In other cases (Fig. 91B) the patch

Fig. 91. The Beginnings of Eyes. (From Plate, after Linko.)

A. Section of an ocellus, or eye spot, at the base of a tentacle of
a jellyfish. B. Section of a "goblet eye" of a jellyfish.

(From Allgem. Zool., Gustav Fischer.)
For details, see p. xxxv.

sinks below the surface, forming a pouch lined
with pigment. Between the large deeply pig-
mented cells on the inside of the pouch are small
"rods" at one end of the "light cells." Such an
alternation of two kinds of cells foreshadows the
alternation of the "rods" and "cones" of more
advanced types of eyes, in which the "rods" are

believed to detect light and darkness, form and

175

OUR FACE FROM FISH TO MAN

movements, while the "cones" chiefly detect color
differences (Plate, 1924, p. 705). In the jelly-
fishes the cavity of the optic pouch is often filled
with a transparent jelly-like substance correspond-
ing to the "glass body" or vitreous humor of
higher eyes, and functionally to the lens. That
these organs are really eyes, says Plate (1924, p.
428), follows from the fact that if the animal is
deprived of them it fails to react in its normal
way to light.

In some of the flatworms the eyes consist of
hollow capsules derived from an infolding of the
epithelium and deeply lined with pigment. Each
capsule has sunk beneath the epithelium, which
has grown over it. It is open on one side and
into its hollow interior project the flower-like ends
of the "light cells," the outer ends of which pass
into elongate nerve cells. Hesse (quoted by
Plate, p. 433) notes that if two such capsules are
symmetrically arranged on either side of the mid-
line, then a light in front will give symmetrically
placed shadows inside the capsules, a light on the
left side will illuminate the left capsule and leave
the interior of the right one in shadow, and so

forth. Thus the nerves inside the capsules on

176

OUR BEST FEATURES

opposite sides of the body will be stimulated
differently according to the direction of the light

Fig. 92. Eye Capsules of Flatwobm: (B) Section of "Goblet
Eye" (from Plate after Hesse); (A) Location of Eyes
(after Parker and Haswell).
(B, from Allgem. Zool., Gustav Fischer.)

For details, see p. xxxv.

and according to their own orientation in the
body. Here the function of paired eyes in enabl-
ing the organism to adjust its own axis of locomo-
tion to the direction of the light comes into view.

177

OUR FACE FROM FISH TO MAN

Indeed, Plate (1924, pp. 738-742) cites much
evidence for his view that the paired eyes of
vertebrates originated as directional organs, guiding
the animal toward the light and that later by acquiring
a lens they became true visual organs.

Fig. 93. How the Eye Capsules of a Flatwoem Serve as Direc-
tional Organs (from Plate, after Hesse).

The arrows show the varying directions of the light. In each
case only a particular part of each retina is stimulated, the rest being
in shadow.

(From Allgem. Zool., Gustav Fischer.)

The higher invertebrates exhibit eyes in all

grades of evolution, from the simple types described

above to the compound eyes of crustaceans and

insects and to the elaborately constructed paired

eyes of the higher molluscs. Eyes occur in various

parts of the body and sometimes in great numbers,

as in certain deep-sea cephalopods. The common

scallop (Pecten) has numerous eyes along the

scalloped edge of the mantle. Thus in typical

invertebrates the eyes are essentially derivatives

of the skin and may occur almost anywhere on the

178

OUR BEST FEATURES

surface of the body, but in the vertebrates the

paired eyes are essentially an outgrowth of a

definite part of the forebrain, only the outer parts

of the eye (including the lens and cornea) being

contributed by the epithelium ; although eventually
.1

cor11'
iris

eyelid

0ptganq2,
opinir.

cart!.

Fig. 94. Eye of Squid (Horizontal Median Section). (From
Plate, after Hensen.)

(From Allgem. Zool., Gustav Fischer.)

the brain itself has been derived from the same

primary outer layer or ectoderm.

Among all the hosts of invertebrates the paired

eyes which at first seem to approach the vertebrate

type most nearly are found in some of the ceph-

alopod molluscs, especially the squids and

179

OUR FACE FROM FISH TO MAN

octopuses. In these highly elaborate organs there
are eyelids in front of the eyes, a contractile iris,
muscles of accommodation, a highly complex
retina of many layers, a large optic nerve and
muscles to move the eyeball. But when we
compare the parts of these cephalopod eyes with
those of vertebrates we find many striking and
profound differences. Thus in the squid (Sepia)
the lids serve as a pupil, there are two corneas,
the outer one perforated, the inner one dividing
the lens into inner and outer parts; the so-called
iris lies entirely outside of the retinal layer instead
of next to it as in the vertebrates; and there is
apparently no true choroid layer. More important
still, in the cephalopods the optic nerve lies
entirely behind the retina, while in vertebrates it
pierces the retina and is then distributed over its
front surface; finally, in the cephalopods the rods
are on the front layer of the retina, pointing
toward the light, while in the vertebrates they are
on the back layer of the retina and point in the
opposite direction.

Not all the cephalopods have eyes as compli-
cated as the type described above and there is a

gradation of forms leading back to the very

180

OUR BEST FEATURES

simple eye of Nautilus (Plate, 1924, pp. 474-478).
The retina and indeed the whole eye of cephalopods
develops in the embryo as a pouch in the skin, and
is thus comparable only to the lens of vertebrates;
in the latter the retina is developed from the optic

cor1

iru

corZ-

Fig. 95. Development of the Eye in Cephalopod Molluscs.

(After Plate.)

(From Allgem. ZooL, Gustav Fischer.)

For details, see p. xxxvi.

cup, which is an outgrowth of the brain. Thus

at every important anatomical point the paired

eyes of cephalopods and of vetebrates differ

profoundly from each other. From all this it is

evident that the paired eyes of cephalopods and

of vertebrates are not homologous with each other

at all, that they have arisen from dissimilar

beginnings and have come to resemble each other

181

OUR FACE FROM FISH TO MAN

by convergent evolution in adaptation to similar
functional needs.

The paired eyes of the modern Limulus and the
scorpions represent specialized offshoots of the
annelid and primitive crustacean types (Plate,
1924, pp. 537-561). Patten and others have
attempted to show how they might have been
tranformed into the vertebrate eyes, but most
authorities consider that there is no direct evidence
in favor of this view and the profound differences
between the eyes of arthropods and those of
vertebrates have always been considered a grave
objection to Patten's theory of the origin of the
vertebrates from arthropods related to the euryp-
terids and to Limulus.

ORIGIN OF THE PAIRED EYES OF VERTEBRATES

We have seen above that a comparative study
of the eyes of invertebrates shows several steps
in the evolution of such elaborately constructed
paired eyes as those of the cephalopods and there-
fore gives us a general idea how the somewhat
similar paired eyes of vertebrates may have been
produced. More direct evidence as to the origin

of the vertebrate eye is wanting. The lancelet

182

OUR BEST FEATURES

Amphioxus, which, as all beginners in zoology learn,
supplies us with an ideally simplified chordate,
goes too far for our present purpose in the simplifi-
cation of its eyes, which have either vanished
entirely by degeneration or never developed.

^ B lc.

Fig. 96. Light Cells of Amphioxus: (A) Forepart of a Young
Amphioxus, Enlarged; (B) Cross-section of the Spinal Cord of
Amphioxus (from Plate, A, after Joseph, B, after Hesse.)
(From Allgem. Zool., Gustav Fischer.)
For details, see p. xxxvi.

According to Plate (1924, p. 494) the lancelet
(Amphioxus) when resting on the sandy bottom
is supposed to sense the direction of the light by
means of long rows of minute eye-like organs,
which are deeply buried in the spinal cord and
extend along each side of the back above the
notochord. Each little eye consists of a single
cell, supposed to be sensitive to light, backed by
another cell which is concave and deeply pig-
mented. A much larger spot of pigment at the

183

OUR FACE FROM FISH TO MAN

front end of the brain tube is interpreted by
Plate (1924, p. 493) not as an eye at all, as it
lacks light cells, but as the last remnant of a
balancing organ. Thus the light-sensing apparatus
of Amphioxus is of the utmost simplicity and has
little obvious relation to the highly complex paired
eyes of vertebrates.

In the foregoing pages we have reviewed the
general construction of paired eyes, we have out-
lined the evolution of eyes from very simple
beginnings, we have considered the wide contrast
between vertebrates and invertebrates in the
structure of the paired eyes and we have seen that
according to present evidence the vertebrate
paired eyes do not appear to be inherited from
any of the more complex invertebrate types but
seem to have arisen in the very ancient and still
undiscovered pre- vertebrates. As direct evidence
from successive fossil stages illustrating the origin
of the paired eyes of vertebrates is meager or
wanting and as there are apparently no surviving
pre-vertebrate stages except possibly Amphioxus,
we must rely chiefly upon the evidence afforded by
embryology, and such evidence is often open to

the suspicion that we may be mistakenly inter-

184

OUR BEST FEATURES

parapineal pineal

pmea.2

pi'necd

retitM.

lens

opticnertre

G " H I

Fig. 97. Evolution of the Vertebrate Eye as Conceived bt
Studnicka (from Plate, after Studnicka).

(From Allgem. Zool., Gustav Fischer.)
For details, see pp. xxxvi, xxxvii.

185

OUR FACE FROM FISH TO MAN

preting as a repetition of long past adult stages
such arrangements or conditions as may be merely
adaptations of the growing embryo to its own
physiological needs.

Studnicka (quoted by Plate), basing his theory
chiefly on the embryology of the lampreys and
their relatives (which may represent the degenerate
descendants of the ostracoderms) , holds that
originally there were two pairs of paired eyes in the
pre-chordates, one pair dorsal, on the top of the
head, consisting of the pineal and parapineal
organs, the second pair low down on the sides of
the head, the eyes of later vertebrates. Both
pairs were derived from patches of cells sensitive
to light, located in the broad sensitive tract that
later folded up to become the brain tube. Up to
this time both sets of eyes had served merely to
orientate the animal with reference to the direction
of light. When as a result of its growing mass the
primitive nerve tract swelled outward, its crests
grew upward and curved over toward the mid-
line, carrying the primary optic depressions on to
its inner side, so that the future "rods" would
now point away from the light, and their nerve

fibers, formerly beneath them, would now be bent

186

OUR BEST FEATURES

around toward the outer surface. Meanwhile the
dorsal pair near the front edge of the brain tract
were not turned over, so that their retina remained
on the outer side of their nerve layer. As the brain
swelling increased it pressed the future optic cups
against the epithelium on the surface of the head;
the epithelium sank inward, folded up into a lens,
and the lens in turn increasing rapidly, conditioned
the insinking of the optic swelling, which thus
became the optic cup. The optic stalk or nerve
is simply the constricted part between the brain
and the cup. By this time the lateral paired eyes
were becoming true organs of vision, while the
dorsal pair gradually degenerated and their nerve
stalks finally became the pineal and parapineal
organs of the brain. It is important to remember
that the retina apparently represents an inverted
patch of epithelium and that the layer of nerve
fibrils now covering it represents the former
underside of the patch. Also that the optic cup
was pushed in from the outside so that its primary
cavity was squeezed out of existence.

The lens is at first connected with its parent epi-
thelium by a slender stalk, which is soon lost. The

lens thus finds itself protruding into the hollow side of

187

OUR FACE FROM FISH TO MAN

the pushed-in ball, or optic cup. The space between
the lens and the inside of the cup becomes filled with
fibrillar tissue which gives rise to the transparent
jelly-like substance called the vitreous humor.

The retina, derived from the inner layer of the
cup, comprises the following series of layers: the
innermost of these is a layer of nerve fibers and
ganglion cells which are gathered together and
pierce the center of the cup, issuing from it as the
optic nerve; next follow various layers of large and
smaller nerve cells, culminating in the layer of
cones and rods, the latter being nearest the outer
epithelial layer of the inner wall and directed
away from the source of light. The outer layer
of the optic cup gives rise to the pigmented layer
of the retina, which doubtless provides the neces-
sary opaque, light-proof layer, like the black inner
surface of a camera. Next comes the network of
blood vessels of the choroid, while outside of the
choroid is the thick sclerotic layer, which is
continuous in front with the cornea.

ORIGIN OF THE HUMAN EYES

Before attempting to trace the evolution of the

human eye, let us recall its broader structural

188

OUR BEST FEATURES

features. We know that it is essentially like a
camera, with its dark chamber (the inside of the
eyeball), its lens, its sensitive plate (retina), its
iris-diaphragm for regulating the amount of light
admitted through the pupil. We know also that
it differs from an ordinary camera in altering the
focus not by regulating the distance between the
lens and the plate but by changing the curvature
of the elastic lens through the pull of the ciliary
muscles. We also know that the human eye
differs from a single camera in being linked with its
fellow of the opposite side so as to provide for
a binocular, stereoscopic mental image and that the
two eyes are biconjugate, that is, by means of its
six eye muscles (Fig. 98), each eye can move in
harmony with its fellow so as to keep a moving
object in focus; also that the eye is a living
mechanism provided with elaborate systems for
the elimination of waste, for automatic renewal
of all parts and for the lubrication, cleaning and
protection of its exposed surface.

The retina carries a coloring matter named
rhodopsin or visual purple, * which becomes rapidly
bleached on exposure to sunlight. No doubt the

1 Cunningham, D. J., 1902, Textbook of Anatomy, p. 689.

189

OUR FACE FROM FISH TO MAN

extent and intensity of the bleaching effect is in
some way proportional to the size of the aperture,
the intensity of the light and the length of exposure.
And no doubt also the innumerable rods and

olliauus superior

rectus
superior

^\\v\\V

Fig. 98.

The Right Eyeball and Its Six Muscles (from Plate,
after merkel and kallins).

(Prom Allgem. Zool., Gustav Fischer.)

cones of the visual field react differently to different
wave lengths (colors) and different intensities
(light and shade), so that an image made up of
innumerable points, like a half-tone picture, is
recorded on the retina. But whereas the photog-
rapher proceeds after an interval to fix the image

190

OUR BEST FEATURES

on the plate, the retina immediately proceeds to

" tele visualize " its images through the myriads of

nerve fibers covering its surface. After passing

through many microscopic relay and "booster"

stations the disturbances pass along a vast cable

route known as the optic nerve. Instantly

reaching their first main destination, the visual

cortex of the brain, the visual currents now incite

millions of repercussions which are flashed and

reflashed to the relay stations and great central

systems in many parts of the brain, where they

set off many triggers that control the secretory

activities of glands or the contractility of muscle

fibers.

The foregoing description holds in a general way

for the eye of vertebrates of all grades from fish to

man, the vertebrate eye, except in degenerate

forms, being extraordinarily constant in its main

features. Hence the basic features of the human

eye date back to the beginnings of the vertebrates

and are fully exemplified in such primitive forms

as the sharks (Fig. 99) . The six eye muscles of the

human eye (Fig. 98) likewise date back at least

to the shark-like stage. Here again the shark is

vastly nearer to man in the essential features of its

191

OUR FACE FROM FISH TO MAN

morphology than it is to any known invertebrate.
In other words, while we can only surmise what the
history of the eye may have been below the verte-
brate stage, we have the most convincing evidence
that once that grade of organization of the eye had

ciliary .

fnusctes cornea- **

rectus #kl3|? sclera

Muscle ^Sfftii/iSmn
ofsHull

Fig. 99. The Right Eye of a Shake in Horizontal Section
(from Plate, after Franz).

(From Allgem. Zool., Gustav Fischer.)

been attained, it was transmitted by heredity with

only minor improvements from fish to man.

Although the human eye is undoubtedly derived

remotely from one that was in general like the

shark type (Fig. 99), from which it has inherited

even the principal layers of the retina, it shows also

many progressive changes beyond that of the shark

in adaptation to vision in the air rather than in

water. Its lens, being relatively smaller and

192

OUR BEST FEATURES

flatter than that of the shark, gives a longer focus,

and accordingly the focal axis of the bulb is

lengthened, the human bulb being spherical while

that of the shark is flatter in front. The cornea in

cornea.

Fig. 100. Diagram of Horizontal Section of the Right Human
Eye (Simplified from Plate, after Luciani).

(From Allgem. Zool., Gustav Fischer.)

man is more convex and widely separated from the

lens, which is entirely behind the iris, whereas in

many sharks it protrudes through the pupil and

touches the cornea. The human lens is much more

delicate, less dense, more easily compressible than

that of the shark and it readily responds to the pull

of the ciliary muscles of accommodation.

193

OUR FACE FROM FISH TO MAN

As to the external accessories of vision, man
retains a vestige of the nictitating membrane or
third eyelid of lower vertebrates in his semilunar
fold at the inner corner of the eyelid; but he has
advanced far beyond the shark in possessing an
elaborate lacrymal or lubricating apparatus, con-

plica sewiluxarit
' ', taruncuiCL

I loccryyyia?

tacrywail

Fig. 101. Tear-draining Canals of the Eye (after Keith).

sis ting of tear-producing glands, with two collect-
ing canals above and below the caruncula. These
two canals converge toward and drain into the
lacrymal sac, which is lodged in a pocket of the
lacrymal bone on the inner wall of the orbit;
the lacrymal sac is continued downward through
the naso-lacrymal duct into the nasal chamber.
Man also has fleshy, movable eyelids, which are pro-
vided with eyelashes and Meibomian glands.

Many similar details could be cited in which

the human eye is superior to that of the shark; but

194

OUR BEST FEATURES

the anti-evolutionist could find little justification
for setting man apart from the rest of creation on
this account, for we find that every one of the
characters cited above is the common property of
normal land-living mammals and that the evolution
of some of these structures, such as the lacrymal
apparatus and the third eyelid, can be traced with
convincing detail through the various branches of
the vertebrate tree lying between the human and
the shark branches.

Moreover we are compelled to cause even further
distress to the indomitable critics of the Darwinian
theory of human origin by bringing forward again
their special horror, the anthropoid apes and
monkeys. For nowhere will more convincing mor-
phological evidence of the relatively very close re-
lationship of man to these animals be found than
in a detailed comparison of the anatomy and
physiology of the paired eyes. And when to these
resemblances in the visual organs between man
and anthropoid, we add the striking identity in the
complex arrangements and connections of the optic
tracts within the brain, as reported by the lead-
ing students of the human and anthropoid brains,

the evidence for Darwin is heaped still higher,

195

OUR FACE FROM FISH TO MAN

The position of the eyes in the human head has
likewise been inherited from the common man-
anthropoid stock. In Notharctus, a primitive
primate of the Eocene epoch (Fig. 35A) the eyes
were directed partly outward as well as forward,
the large muzzle extended far in front of the orbits
and binocular vision was obviously impossible. The
large size of the olfactory chamber in Notharctus
also indicates that like other mammals and
especially like its relatives the modern lemurs, the
lowest existing primates, it still depended largely
upon its olfactory sense, while the higher primates
have a much reduced olfactory apparatus and a
predominant visual apparatus. With regard to
the direction of the orbital axes, these look partly
outward also in most of the modern lemuroids
(Fig. 35B) and even the greatly enlarged orbits
of the modern Tarsius (Fig. 35 C) are directed
somewhat away from each other. In the South
American monkeys (Fig. 35D) however, the outer
angles of the orbits are shifted further forward and
the muzzle is reduced; in the Old World monkeys
and anthropoid apes (Fig. 35E, F), this process is
completed and binocular vision is established. The

binocular character of the vision of anthropoids and

196

Fig. 102. Front View of Infant and Young Skulls of

Anthropoids (A, B, C) and of Man (D).

For details, see p. xxxvii.

197

OUR FACE FROM FISH TO MAN

man is especially evident in the front views of the
young skulls (Fig. 102).

Meanwhile we observe a general progression in
the character of the hands, which in the lemuroids
are hardly more than forefeet, while in the gibbon,
chimpanzee and gorilla the anterior extremities
are true hands, adapted primarily for brachiation
or leaping with the arms, a habit which requires the
greatest quickness in adjusting the focus of the
eyes and in correlating the locomotor activities
with the rapidly changing visual data.

To the brachiating habit of his ancestors man
doubtless owes much of his skill in discriminating
the relative nearness of different objects. Brachia-
tion would also seem to be greatly facilitated by
bicon jugate movements of the eyes. Broman and
John I. Hunter have shown that in the chimpanzee
the nucleus in the brain of the oculomotor nerves,
which controls several of the eye muscles, has
essentially the same pattern as in man and differs
widely from that of the lower primates which have
not attained bicon jugate movement of the eyes.

The surface of the iris as seen through an
ophthalmoscope differs widely in different kinds

of animals. Lindsay- Johnson in his beautiful

198

OUR BEST FEATURES

monograph on the fundus oculi of vertebrates
figures the retinal surface of the eye of many
mammals, including a white man, a negro and a
chimpanzee. The deeply pigmented iris of the
chimpanzee shows the most striking resemblance
to that of the negro, while its basic similarity to
that of the white man is masked by the loss of
pigment in the latter. Only man and the apes
have a macroscopic "macula lutea" or spot of
clearest vision on the retina (Plate, 1924, p. 690).
The lacrymal bone, in the inner corner of the
eye, affords additional evidence of the close
relationship of man and the anthropoids. Not
only are its general form and connections strikingly
similar in man and chimpanzee (save for the very
small size of the "hamular process" in the apes)
but Le Double notes1 that in Deniker's gorilla
foetus the lacrymal bone begins to ossify in the
same place that it does in the human fcetus to-
ward the end of the fourth month, namely, in the
covering membrane of the ethmoidal cartilage
and on the inner side of the lacrymal sac; that,
like the human foetal lacrymal, it consists of an

1 " Essai sur la Morphogenie et les Variations du Lacrymal et des
Osselets peri-lacrymaux de l'Homme." Bibliographie Anatomique,
1900, T. VIII, p. 125.

199

OUR FACE FROM FISH TO MAN

oval plaque with its long diameter inclined
obliquely from above downwards and from within
outward. Le Double further notes1 that during
intrauterine life the human lacrymal is successively
oval, triangular and quadrilateral in form, that
the lacrymal of the gorilla is almost triangular,
while those of the adult chimpanzee and orang,
which show so much resemblance to the human
lacrymal, are also subject to the same variations
in form.

CONCLUSIONS

In conclusion, the human eyes owe their begin-
nings to the sensitivity of protoplasm both to the
injurious and the beneficial effects of light. In
their early pre-vertebrate stages they seem to
have been merely directional organs to orientate
the animal's locomotion with reference to the
light, serving the same purpose at the lower sides
of the head as the pineal and parapineal eyes did
on the top of the head (Fig. 97 A). At this stage
the eyes were still on the inner side of the brain
tube. When the brain grew outward into contact
with the epithelium the optic cup acquired a lens

Ibid., pp. 128, 129.

200

OUR BEST FEATURES

and true vision resulted, greatly enhancing the
organism's success in the pursuit of living prey
and in the escape from its enemies. Then various
accessory organs appeared, for regulating the focus
of the lens, either by slightly changing its position
with reference to the opening, or by altering its
curvature. After the air-breathing fishes crawled
out of the swamps their eyes had to become
accustomed to functioning in the air and we find
further improvements in the accessory devices for
accommodation and for protecting and keeping
in repair the whole delicate apparatus. These
devices culminate in the mammals, in which
however for the most part the olfactory ap-
paratus rather than the eyes is still the dominant
sense organ. The primates, alone, show a pro-
gressive reduction of the olfactory sense and a
concomitantly increasing importance of the eyes,
which is further emphasized in the arboreal
brachiating anthropoids. In man, a secondarily
terrestrial offshoot of the primitive anthropoid
stock, the eyes retain not only all the advantages
won by the vertebrates in their earlier predatory
career, but also all the improvements resulting

from a prolonged course of very active life in the

201

OUR FACE FROM FISH TO MAN

trees. Starting with all this experience the eyes
of the first true man not only cooperated with
the hands, but filled the brain with memory
pictures, and these, on the principle of conditioned
reflexes, came to be associated in definite com-
binations with the memories of vocally produced
sounds. Thus mans eyes and ears, rather than his
nose, provided him with the means of rising above
the endless round of life known to his predecessors, of
turning his observational powers upon himself, and
eventually of foreseeing not only the immediate but
also some of the distant effects of his own activities.

Primitive Sound Recorders

The human organ of hearing (Fig. 103) consists
of three main parts: (1) the external ear, for collect-
ing the sound waves; (2) the middle ear, including
the tympanic or drum-membrane and the tym-
panum or middle-ear chamber, the latter con-
taining the three auditory ossicles, the office of
which is to transmit the vibrations of the drum
membrane to the inner ear; (3) the inner ear, or
labyrinth, comprising (a) the three semicircular
canals with their basal connecting chamber or

utriculus, the canals and utriculus being concerned

202

semicircular
canals

f labyrinth
[inner ear J\

v. s

incus

cochlear

IK!' outer ip'zpfjM!!

: ~ fin

middleearcairity stapes drummem&rane ">

(Tympanumy

$Mv... ascending

life

cochlearduct

B "**

tjspiralduct

branches of
hearing nerire

Fig. 103. The Human Organ of Hearing and Balance.

(A) Transverse section (after Cunningham); (B) Diagram section of
the cochlea; (C) Greatly enlarged view of the cochlear duct.
{For details, see pp. xxxvii, xxxviii.

203

OUR FACE FROM FISH TO MAN

with the sense of balance; (b) the cochlea, a
spirally-wound double tube filled with liquid and
containing between the upper and lower inner
tubes the spirally-wound organ of Corti, the true
organ of hearing. The sound waves in the air
cause the drum membrane to vibrate, the ossicles
magnify the movement and set up mechanical
waves in the liquid of the cochlea. It is these
mechanical waves and not the sound waves them-
selves that are picked up by the little rods of the
organ of Corti and transmitted to the nerves of
hearing.

In the more primitive fishes at the lower end
of the vertebrate series there is no middle ear and
the inner ear consists chiefly of the semicircular
canals, which may be followed throughout the
series without a break from fish to man.

The labyrinth arises in the embryo shark, as in
the embryo man, by the formation of a sac or
pocket in the ectoderm or outer cell layer on either
side of the tube that gives rise to the hind brain.
The sac later becomes surrounded by cartilage
which finally ossifies. The nerves of the semi-
circular canals appear to be part of the fore and
aft series that innervates the "ampullae" of the

ttictolymphaTicctuct

anterior
canal

posterior
'canat v -

posterior.
rcanal *

enetotymph
dud

cochlea

Fig. 104. Series Showing the Membranous Labyrinth or Inner

Ear from Fish to Man. Right Side; Outer

View. (After Retzius.)

A. Shark; B. Ganoid fish; C. Primitive reptile; D. Alligator; E. Rabbit;
F. Man. For details, see p. xxxviii.

205

OUR FACE FROM FISH TO MAN

shark (Fig. 6) and the lateral line organs in the
skin of most fishes. These organs are sensitive
to the disturbances caused in the water either by
wind or by objects falling on the surface of the
water (G. H. Parker). Below the semicircular
canals there is a sac-like depression (Fig. 104 A)

Fig. 105. Development of the Labyrinth or Inner Ear of

Man (after Streeter).

frequently containing an otolith or calcareous
secretion which may function in the sense of bal-
ance. The nerve that goes to the semicircular
canals also sends off a branch which is attached
to the otolith, and this lower branch, in the higher
vertebrates, is the nerve of hearing (Fig. 104D-F).
It is doubtful whether fishes can really hear
rather than feel sound waves in the water. The
true organ of hearing equivalent to the cochlea of

man has its inception apparently in the Amphibia

206

OUR BEST FEATURES

in the shape of two small papillae which grow out
from the side of the sac below the semicircular
canals. In the crocodiles and alligators one of
these papillae is prolonged into a curved tube
(Fig. 104D) and in the mammals (Fig. 104E, F)
the tube is wound into a spiral, the cochlea. Thus
while the semicircular canals which are concerned
with balance show only minor changes as we pass
through the long series from shark to man, the
organ of hearing in air has its beginnings in the
Amphibia and culminates in the typical mammals,
from which it is transmitted intact to the apes
and man.

The chamber of the middle ear (Fig. 106) in
the frog (which represents a comparatively little-
modified survivor of the earliest amphibians) is
derived in the embryo from an out-pocketing from
the throat, corresponding to the first or hyoid
gill pouch of fishes. This chamber is therefore
lined with the entoderm, or primary inner cell
layer. The Eustachian tube of the frog is the
short passage connecting the cavity of the middle
ear with the cavity of the throat. By this arrange-
ment the outward pressure of the air inside the

mouth and throat neutralizes the inward pressure

207

OUR FACE FROM FISH TO MAN

of the air outside the ear-drum. Likewise in all
higher vertebrates, including man, the cavity of
the middle ear communicates with the throat
through the Eustachian tube; this arises in the

semicircular
canals

tympanic
' ring

wedutta__

oblongata^

acoustic
nertre

throat

tympanic
membrane

Stapes

tympanic
ycmty

Eustachian
tube

Fig. 106. Transverse Section of the Head in a Frog, Showing

the Relations of the Middle Ear (there is no Outer Ear)

to the Inner Ear and of the Latter to the Brain (after

T. J. Parker and W. N. Parker).

embryo as an outgrowth of the primitive throat
cavity immediately behind the first or jaw arch
(Frazer, quoted by Keith).

The tube of the outer ear of mammals corre-
sponds in position partly to the spiracle or hyoid
gill cleft of the shark. Both arise also in the
embryo as a down-pocketing of the ectoderm,

which meets an out-pocketing from the throat

208

OUR BEST FEATURES

cavity called the hyoid gill pouch. In the stur-
geon, a survivor of the primitive ganoids, W. K.
Parker's plates of a very young embryo show the
hyoid gill cleft lying in front of the upper part of
the hyomandibula, or upper segment of the second
gill arch. A spiracular cleft was also present in

Olfactory
pit J

Fig. 107. Embryo Sturgeon, Showing Gill Clefts
(after W. K. Parker).

the oldest fossil lobe-finned ganoid Osteolepis

(Watson). In the earliest known amphibians and

reptiles the spiracular cleft may be represented

in part by the otic notch (Figs. 17, 19) upon which

the tympanic membrane was stretched. In the

fishes the gill chamber behind and below the

spiracle was covered externally by the bony

opercular flap, but in the oldest known amphibians

this bony gill cover has disappeared, leaving the

prominent otic notch open behind.

209

OUR FACE FROM FISH TO MAN

In the frog, a modern representative of the
Amphibia, there is no external ear tube, since the
tympanic membrane lies on the surface (Fig. 106).
In the reptiles a ridge or fold of skin may guard
the drum membrane and in the birds and typical
mammals the latter has sunk so far below the sur-
face that a deep tube is formed.

That the mammalian outer ear tube corresponds
only at most in part with the spiracular pocket of
the shark is indicated by the fact that the outer
ear tube of mammals is formed below the Eustach-
ian tube (which represents the lower part of the
first internal gill pouch), while in fishes the spir-
acular pocket is formed from the upper part of
the spiracular cleft and lies above the first internal
gill pouch.

In Echidna, one of the egg-laying mammals,

G. Ruge found that the cartilage of the external

ear was continuous with the hyoid, or second gill

arch, and hence the inference was drawn that the

external ear cartilage was derived from the hyoid

arch. But Gaupp's figures of the embryo Echidna

show the hyoid cartilage entirely distinct from the

external ear. And the relations of the ear tube

to the tympanic ring both in Echidna and in other

210

OUR BEST FEATURES

mammals indicate that its cartilage is a new local
development in the mammals.

The outer ear in mammals takes on a great
diversity of forms, from the trumpet-like ear of
antelopes and other keen-eared, defenceless herbi-
vores to the huge and imposing ear-flaps of the

Fig. 108. Human (A) and Macaque (B) Embryos, Showing Origin

of the External Ear from Six Tubercles. (From Leche,

a, after selenka, b, after hls, keibel.)

(From Der Mensch, Gustav Fischer.)

African elephant. Some of the bats have large

ears of extreme complexity, while the whales have

only a thread-like tube beneath the skin that

marks the last vestige of the external ears. Very

little in detail is known either about the precise

functioning of the different forms of external ear

or about the origin and significance of its many

subdivisions, such as the tragus, antitragus, crus

of the helix and antihelix and the marginal fold or

211

OUR FACE FROM FISH TO MAN

descending helix and lobule. According to Keith
(1921) in the human embryo of the sixth week all
but the marginal fold arise from six tubercles that
form around the first gill cleft depression.

Three of these tubercles [writes Keith] grow from the
mandibular or first arch and form the tragus, crus of the
helix, and helix; three from the hyoid arch to form the
lobule, antitragus and antihelix. The hinder margin of the
ear, or descending helix, with the lobule, arise as a mere
thickening or elevation of the skin behind the tubercles in
the hyoid arch. Later in development the tubercles of
the helix and antihelix send out processes which cross the
upper part of the cleft and obliterate it, while the neigh-
boring tubercles fuse to form the definite parts of the ear.
The posterior margin and lobule rise up at the same time
as a free fold.

Fig. 109. Ears of Fcetal Macaque (A) and of a Six Months

Human Fcetus (B). (From Plate, after Schwalbe.)

(From Allgem. Zool., Gustav Fischer.)

The common lemur {Lemur catta) of Madagascar
has very large pointed ears that can be directed
forward. In the monkeys the ear tends to
be flat with a rounded top, quite different
from the trumpet-like ear and not capable of

being thrust far forward. The ear of the Old

212

Fig. 110. Extehnal Ears of Anthropoids and Men.

(After Keith.)

A. Chimpanzee; B. "Small chimpanzee type" (human); C. "Chim-
panzee type" (human); D. Orang; E. "Orang type" (human);
F. Gorilla; G. Gibbon; H. Lemuroid (Nycticebus).

213

OUR FACE FROM FISH TO MAN

World or catarrhine monkeys shows various stages
in the reduction of the pointed tip (cf. Pocock,
1925, Fig. 36). The ear of a six-months' human
foetus (Fig. 109B) figured by Schwalbe has a
truncate upper rim and vestigial tip and in general
appearance approaches the Old World monkey
type (Fig. 109 A) as noted by Schwalbe. The un-
rolled outer rim and Darwin's point, found as an
occasional variant in man, is reminiscent rather of
the monkeys than of the anthropoids, although
indications of the Darwin's point are not lacking
in certain chimpanzees (cf. Haeckel, 1903, PL 26)
and in certain orangs (Pocock, 1925, Fig. 37D, E).
The ears of the great anthropoid apes, while
highly variable in details, are substantially of the
human type, especially those of the gorilla. All
have the rolled-over upper rim, but in the chim-
panzee the hinder rim, according to Pocock (1925)
is "sometimes flat, sometimes slightly overfolded
but never apparently so overfolded as is typically
the case in Homo. The lower lobe, varying in
size, is not so well developed as in Man." On the
whole the external ears of the gorilla and chim-
panzee are remarkably human in appearance and,

like so many other features of anthropoid anatomy,

214

OUR BEST FEATURES

they are literally one of the earmarks of man's
relatively close relationship to the primitive brachi-
ating ancestors of the chimpanzee-gorilla stock.
If man had been derived from some entirely differ-
ent stock of Primates there is no assignable reason
why he should resemble the gorilla and the chim-
panzee in so many external and internal characters
in spite of his widely different habits and notwith-
standing the millions of years that have passed
since the human and gorilla-chimpanzee groups
began to separate.

Since the time of Darwin the reduced ear
muscles of man have been justly famous as indi-
cations of our derivation from mammals with
more movable ears. Ruge's monograph (1887,
Plates V, VI, VII) on the facial musculature shows
very clearly the striking resemblance between the
ear muscles of the chimpanzee and those of certain
human embryos and children (cf. also Fig. #3D, E) .

The evolution of the auditory ossicles (Fig. Ill)

has been referred to earlier in this book but may

be summarized here as follows. The most ancient

member of the ossicular chain is the stapes, or

stirrup, which has probably been derived from

one of the two upper segments of the second or

215

OUR FACE FROM FISH TO MAN

hyoid gill arch of fishes. In the oldest known
amphibians, as in the frog (Fig. 106) the stapes

handle
fleverarm\
\ol malleus J

attic

jneus(anvil)

cootooth

joint

foolplateof
stapes (stirrup) %
fits into mnerear *

9"°** Sustac,

tube

tendon of
restating
muscle

. drum
membrane

tympanicr/m

headof malleus
' (hammer)

chorda tympaniX
"-'"? through
middle \
itfarcfiam&eri

lan

tensor tympani
[regulating muscle)

Fig. 111. The Middle Ear of Man, Showing the Auditory

Ossicles (after Cunningham).

For details, see p. xxxix.

extends from the inner ear to the tympanum or
drum membrane. When the tympanum first ap-
peared (in the Amphibia) it was fastened (Fig.

216

OUR BEST FEATURES

17B) to the back part of the squamosal bone, or
bony shell over the back part of the primary upper

STAPES

EXWACOwtlELLA

VAORATE
ART/CUIAR
.-■ANWiAK

SUR

Fig. 112. Relations of the Parts of the Middle Ear in an
Extinct Mammal- like Reptile (after Sushkin).

For details, see pp. xxxix, xl.

jaw. In the reptiles the tympanum is always

associated with this same region and is also more

or less connected with the angular bone of the

217

OUR FACE FROM FISH TO MAN

lower jaw. In the fossil mammal-like reptiles a
large notch (Figs. 112, 113) in the back of the

MALlfUS /A/MS
ART/C. =.QU.

GOA//ALE ^ ;' \V- y

ry/vp
a/\/g

ARVfr(MALLEUS)

Qt/-(/A/C(/S)
QJ

, CARTILAGE

)4A/&-

Fig. 113. Origin of Auditory Ossicles.

(A) Back part of the lower jaw of an advanced mammal-like reptile
(based chiefly on a cast of the specimen combined with observations
and figures of Seeley and Watson); (B) Foetal mammal (slightly
modified from R. W. Palmer). For details, see p. xl.

angular bone is thought for various reasons to

have served for the attachment of a pocket from

the membranous sac that encloses the cavity of

218

OUR BEST FEATURES

the middle ear. The stapes was connected with
the inner ear on the inner side and by its double
outer end (Fig. 112) with both the quadrate bone
and the tympanic membrane. When the dentary
bone became very large and formed the chief part
of the lower jaw, the angular, articular and quad-
rate elements, which were still connected with the
tympanum, became much smaller. When the
dentary formed its new joint with the squamosal
(pages 36-39) the lower jaw bones that were
behind it (quadrate, articular and angular) gave
up their function as jaw elements and intensified
their auditory function, transforming sound waves
into mechanical pulsations and thus transmitting
the equivalents of the sound waves to the stapes;
this in turn passed them on to the liquid in the
inner ear.

In this way arose the marvellous delicate mech-
anism of the auditory ossicles, the tiny muscles of
which (Fig. Ill) are still innervated, even in man,
by twigs from the main nerve of the jaw muscles.
Meanwhile the first gill pouch, below the back
part of the jaw, had grown upward and surrounded
the now reduced angular, articular and stapes,

forming the cavity of the middle ear (Fig. 112).

219

OUR FACE FROM FISH TO MAN

The human embryo, like that of mammals of all
other orders, still shows in the clearest, most unde-
niable way, the origin of the malleus and incus from
the reduced primary jaw elements (Figs. 114, 115).

Ancient and Modern Physiognomy

The art of reading character from the human
face is one of the things that every woman knows
and every man prides himself upon. But the
courts are crowded with the wrongs of deceived
women and the prisons are filled with wolves in
sheep's clothing who have hidden a ravenous heart
behind faces that confident physiognomists, in-
cluding practical men of business, have diagnosed
as honest. What is the matter then with the
popular "science" of physiognomy?

To the ancients, never embarrassed by facts,

physiognomy was as easy as every other branch of

science. Aristotle, according to the Encyclopaedia

Britannica (article on Physiognomy), taught that

noses with thick bulbous ends belong to persons

who are swinish; sharp-tipped noses belong to the

irascible, those easily provoked, like dogs; large

rounded, obtuse noses to the magnanimous, the

lion-like; slender hooked noses to the eagle-like,

220

GOA//ALE

UffiRARTICULARNSK

(A/EAHSO/S)

MALLEUS-ARTICULAR

,_ INCUS
'.^QUADRATE

^AIECKETS
CARTILAGE

STAPES

HYO/O

TYMPAWCtRING
Fig. 114. Relations of Ossicles to Lower Jaw in
Foetal Armadillo (Tatusia hybrida).

(Composed from two figures by W. K. Parker.)

, GOMALE
{PREART/Cl/LAR)

JNCt/S

QUADRATE)

{TYMPANIC
(AA/GUIAR)

ajeckeEs

CARTILAGE »#,|\X

AMUEVS

-1A/CUS
STAPES

'A7AMBR/OH

Fig. 115. The Reptilian Stage in the Development
of the Auditory Ossicles.

A. Lower jaw and attached auditory ossicles in a foetal hedgehog
(after W. K. Parker). B. Lower jaw and attached auditory ossicles in
a human fcetus (after Macklin). For details, see p. xl.

221

OUR FACE FROM FISH TO MAN

the noble but grasping; round-tipped retrousse
noses to the luxurious, like barnyard fowl. This is
the kind of rubbish that passed under the name of
science for more than two thousand years. Other
self-appointed and equally successful teachers
classified men and faces as mercurial, saturnine,
jovial and so forth, according to the positions of
the stars that ruled their fates from birth, so that
physiognomy, like palmistry, was clearly linked
with astrology.

The modern science of physiognomy, if it be a
science, began when artists and sculptors tried to
record the facial expressions of emotions and of
moral character and when actors tried to repro-
duce these expressions on the stage. Much valu-
able descriptive material was thus accumulated
and expressions intended to represent piety, devo-
tion, suffering, anger, malice, joy and the like,
may be seen in any collection of old masters or
any antique treatise on physiognomy.

A great step in advance was taken in 1806 when
Sir Charles Bell in his Essay on the Anatomy of
Expression inferred the action of the mimetic or
facial muscles in producing the characteristic
expressions of the emotions.

Fig. 116. Young Chimpanzee
Showing Facial Expression.

(From a photograph by Herbert Lang.)

OUR BEST FEATURES

The experimental method of studying physiog-
nomy was founded by Duchenne {Mechanisme de
la physiognomie humaine, Paris, 1862), who showed
that by the use of electricity the action of the
separate muscles could be studied and by the
aid of photography accurately represented (Encycl.
Brit., XI Ed., Art. Physiognomy).

In Darwin's book on the Expression of the
Emotions (1872) it was shown that man and the
apes agreed in expressing equivalent emotions by
means of homologous facial muscles (Figs. 23, 24,
116). Thus the subject of physiognomy was
brought under the evolutionary point of view.

At the present time the general subject of
physiognomy or the systematic investigation of
the human face is being pursued according to the
following methods. First, the evolutionary meth-
od, as in the present work, endeavors to answer
the question, by what stages did the human face
arrive at its present form? From the evolutionary
viewpoint each type of face among the lower
animals is associated with a definite pattern of
behavior. Hardly a beginning has been made in
tracing the evolution of behavior or in correlating

the details of facial character with neuro-anatomy.

223

OUR FACE FROM FISH TO MAN

Second, the anthropological method studies the
variations of the face in different races and en-
deavors to arrive at general concepts of pure and
hybrid racial types. Third, the ontogenetic or
embryological method describes the development
and growth of the head as a whole and of its several
parts. Fourth, the genetic method studies the
heredity of facial characteristics, tracing through
successive generations the results of homozygous
and heterozygous matings with reference to par-
ticular features. Fifth, the physiological method
studies the chemical factors of the growth and
development of the face, including those growth-
stimulating substances that the embryo derives
from its parents and those that are produced by
its own various endocrine glands. Sixth, the clin-
ical method notes that certain types of face are
frequently associated with low resistance to cer-
tain diseases and seeks to determine the causes of
this association. Seventh, the psychologic or
behavioristic method endeavors to determine
whether there are measurable correlations between
definite combinations of features and grades of
intelligence. Can an expert predict from exam-
ining faces alone which individuals will score high

224

OUR BEST FEATURES

and which low? Eighth, the student of crime and
criminals endeavors to discover correlations be-
tween certain types of face and constitutional pre-
disposition to crime. Ninth, the psychoanalyst
will undoubtedly seek for traces in every face of
the sore conflict between the "censor" and the
rebellious subconsciousness. Tenth, the psychia-
trist, studying pathologic types of mentality, may
approach his material from any of the above
described paths. Let us see now how much room
there is for the old-fashioned physiognomy.

I undoubtedly inherit the general ground-plan
of my face from my excessively remote shark-like
ancestors who possessed paired olfactory capsules,
paired eyes and paired internal ears, arranged in
the order named, and who had a medium mouth
below the nose and eyes. I also owe to these
humble creatures the framework of my tongue and
vocal organs, my jaw and throat muscles and
many other features both useful and necessary.

Next, I owe to the primitive lobe-finned fishes
or crossopts the complete bony scaffolding of the
face and jaws, which in them lay on the surface but
in my own face is deeply buried beneath the flesh.

Then I owe to the higher mammal-like reptiles

225

OUR FACE FROM FISH TO MAN

the fact that the right and left halves of my lower
jaw are composed of a single piece and that I
have a set of teeth limited to the margins of the
jaws and differentiated into incisors, canines, pre-
molars and molars. I also owe to these hitherto
much neglected animals the "basic patents" for
the delicate apparatus of my middle ear, together
with my bony palate and several other important
parts of my make-up.

In the earliest mammals the bony mask became
covered with mobile, sensitive flesh; to them I
owe also the very hairs of my head, my eyebrows,
eyelashes and other facial accessories.

To my earliest primate ancestors I owe the large
size of my eyes and a considerable part of my
brains.

To my friendly anthropoid ancestors I am

heavily indebted : for eyes that can focus on things

near at hand, that give stereoscopic pictures and

that follow closely the flight of a moving object;

for a nose that is a real nose and not a snout; for

lips that can smile and laugh or curl up in anger

or kiss in love; from them I inherited all my baby

teeth and my thirty-two adult teeth; the very

shape of my ears is theirs.

226

OUR BEST FEATURES

To my early human ancestors I owe the reduction
of my hitherto coarse muzzle and the first training
of my tongue to speak.

To my later human ancestors I owe the improve-
ment of my forehead, the general refinement of
my features and my rather weak jaw.

To the Nordic strain in my ancestry I ascribe
my fair skin and blue eyes, while to both the
Nordic and the Mediterranean strains I owe my
narrow head and a nose of moderate dimensions,
conforming neither to the figure-6 type nor to the
alpine V, nor to any of the concave varieties, but
fairly straight and presentable.

However, when I have determined all this and
much more of the same kind I am still far from
giving a description of my face that would satisfy
the requirements of Scotland Yard, for most of
the features mentioned have been true of millions
of men of all ages. There remains then not only
the exact measurements and proportions but also
the individual history of my face.

Fortunately my development proceeded without
undue mental stress or sudden prenatal shock.
Hence I escaped being a Mongolian idiot. My

ancestors do not seem to have had deficient thy-

227

OUR FACE FROM FISH TO MAN

roids and there must have been a fair sufficiency
of iodine in my food, for I missed being a cretin.
After birth I never developed any notable defi-
ciency in either the hypophysis, the thyroids, the
thymus or other glands, so on all these counts I
missed obesity, and on account of the fair state of
the pituitary I escaped gigantism and acromegaly;
as the adrenals functioned properly, excessive pig-
ment was not deposited in the skin and so I
escaped Addison's disease by a wide margin.

Thus owing to all the favorable circumstances
of my prenatal development I did not "come into
the world scarce half made up" but all the various
parts of my face joined together in the right order,
with no undue accelerations or delays, and so
I escaped many distressing inconveniences such as
a hare lip or a cleft palate. At the right time
before birth I lost the "Mongolian fold" in the
inner corner of my eye; nor was my face marked
with a nsevus. But after birth I had to run the
gamut of children's diseases and no doubt they
checked growth to some extent, leaving me with
a temporarily impaired heart and a little below
the average in stature and weight. On the deficit

side also there was a defective turbinate bone

228

OUR BEST FEATURES

and a slightly warped septal cartilage of the nose,
together with slight malocclusion of certain teeth
and a failure of two wisdom teeth to erupt.

Thus I may explain my face although I cannot
improve it. A specialist in this subject could
afflict the reader with many pages of this sort of
thing; but the chief object here is to raise this
point. Suppose I asked my grocer to open a credit
account on short acquaintance; upon which, if
any, of the features listed above would he decide
to trust me? Would he not trust equally well
many other customers with entirely different types
of face? And do we not see similar artistic talent,
musical talent and traits of leadership, moral
courage, etc., embodied in widely different types
of face? In short, does not scientific physiognomy
and even intuitive physiognomy discount all these
and many other such before coming to the small
residue of features that may conceivably be corre-
lated with particular mental and temperamental
qualities? And in order to detect the abnormal
must one not know at sight the normal range of
variations in all the features in all the races for
both sexes from infancy to old age?

The studies of Keith, Stockard and others on

229

OUR FACE FROM FISH TO MAN

abnormal human types and of Stockard on the
parallelism between abnormal human and animal
types are all leading to a new understanding of
the causes of racial and individual types of faces.
The bulldog and a certain type of human dwarf
with a broad face and retrousse nose equally owe
their peculiar features to a derangement of the
normal functioning of the hypophysis, one of the
growth-regulating glands. This condition is called
achondroplasia and is largely hereditary. In both
the bulldog and the achondroplastic dwarf the
base of the skull ceases to grow and becomes ossi-
fied at an early stage. The rest of the growing
head, being confined at the base, grows out at the
side and the head thus becomes short in proportion
to its width, or brachy cephalic. Similarly the
median cartilaginous septum of the nose is not
pushed forward by the base of the skull, the bridge
of the nose therefore fails to rise up and the nose
remains flat or actually sunken, giving a marked
depression below the forehead. The maxilla, or
upper jaw bone, like the base of the skull, fails to
grow forward and this causes the lower jaw to
protrude beyond the upper, giving a characteristic

"undershot jaw."

230

OUR BEST FEATURES

The opposite condition to achondroplasia is
known as acromegaly and is due to an opposite
disturbance of the normal functioning of the
hypophysis-pituitary complex. It is characterized
by excessive growth of bone in the linear direction.
Human acromegalics are apt to become excessively
tall, their faces growing exceedingly long and their
chins very protruding. Acromegaly is often but
not always associated with gigantism, which pre-
sumably results from an abnormally active thy-
roid gland. Among the dogs, writes Stockard,
the St. Bernard, the mastiff and some others show
symptoms of acromegaly along with gigantism.
The bloodhound, on the other hand, is a splendid
example of the acromegalic type without gigantism
and his facial expression and general appearance
are closely similar to the human acromegalic.

The opposite condition to gigantism, known as

ateleosis, is responsible for the production of true

midgets, which typically grow normally for five

or six years after birth and then stop growing.

They may or may not become sexually mature and

often retain infantile faces. Among dogs the King

Charles spaniel is in "shape, outline and expression

almost a picture of the human midget " (Stockard) .

231

OUR FACE FROM FISH TO MAN

Quite recently Stockard has classified all human
faces under two general types, into which almost
all ordinary persons fall, the "linear" and the

Fig. 117. Stockard's Linear and Lateral Growth
Types (after Stockard).

A. Infant; B. "Linear" adult; C. "Lateral" adult.

"lateral" (Fig. 117). His linear type is that in
which, owing to a high rate of metabolism induced
by a highly active thyroid gland, growth along the
long axis of the body (from the tip of the nose

down the back) greatly predominates over growth

232

OUR BEST FEATURES

in the transverse plane. The linear type is the
faster-growing, thin but not necessarily tall group.
His lateral type, owing to the slower metabolism
of low thyroid activity, is slower in maturing and is
stocky and rounder in form; that is, the transverse
growth components are relatively greater than in
the linear type. Stockard's recognition of these
two types was a result of his long experimental
work on the factors of growth during the embryonic
development of animals. His descriptions of the
types are of such fundamental importance for an
understanding of racial and individual differences
in faces that it is necessary to quote them quite
fully:

Taking the tip of the nose as the extreme anterior point
of the body and viewing the figure laterally, as seen in
figure 1 [118] we may draw a line which would indicate the
morphological lateral line. This line on each side of the
body separates the truly dorsal from the truly ventral
surface regions. When these lines on the two lateral sur-
faces of the head and body are thought of in space we may
imagine that the nearer they come together the more
linear is the individual, and the wider apart they diverge
the less linear and more lateral the individual type will be.
Figure 2 [117] illustrates this in the growth and develop-
ment of the two types from the infant condition.

Examining figure 2B [117B] it is seen that when the
lateral lines are near together the head is of course narrow
or dolichocephalic. The interpupillary distance is short
and the eyes are close together, the nose bridge is narrow

233

OUR FACE FROM FISH TO MAN

and therefore generally high, the mouth arch is narrow
and for the same reason generally high, the lower jaw is
small and narrow and usually not strongly developed.

Fig. 118. Side View of Human Figure, to Indicate the Anterior

Tip and the General Direction of the Lateral

Line (after Stockard).

The teeth are usually crowded and somewhat ill-set. The
neck is long and small in circumference, the shoulders are
square, high and angular, the extremities are long and
slender with long slender muscles and slender bones, the
trunk is short and narrow, tapering to the waist. The
intercostal angle is quite acute. The stomach in such a
person is long and narrow and rather vertical in position,

234

OUR BEST FEATURES

extending to low in the abdomen and the liver is generally
small.

The shape of the eye in this type is such that it is usually
physiologically far-sighted though not pathologically so.
They need no glasses on the street unless for astigmatism
or some pathological condition. They are under weight
for height according to the crude average tables now in use,
and are often so as children. They arrive at puberty rather
early than late and differentiate rapidly so that the males
develop a large strong larynx and a low-pitched bass or
baritone voice. Their skin is thin and sensitive as is also
the epithelial lining of their alimentary tracts. When in
normal health they rarely laugh aloud and when suddenly
shocked they resist the reflex jump and never scream. In
this way they pass for cool, calm individuals with steady
nerve, but as a matter of fact the body is almost constantly
held under nerve control and they are actually nervous,
usually suffering more after a shock than on the occasion.

The lateral type when fully expressed is the antithesis of
the linear type in all of the respects mentioned. The lateral
lines are far apart and the head grows wide and not long
(Brachy cephalic), the interpupillary distance is wide and
the eyes are far apart, the nose bridge is wide and often,
though not necessarily, low. The mouth arch is wide and
low, the teeth are not crowded and are usually smoothly
set. The lower jaw is large and strongly developed. The
neck is short and large in circumference. The shoulders
are round and sloping. The extremities are not long and
are stocky with large bones and thick short muscles. The
trunk is inclined to be long and full, not constricted but
bulging at the waist. The intercostal angle is quite obtuse.
The stomach in such a person is large and tends to be
transverse and high in position, the liver is generally large.

The eye in the lateral type is so shaped as to be anatomi-
cally near-sighted instead of far and such persons frequently
wear glasses on the street. This type is well rounded and
over weight for height and also shows great fluctuations in

235

OUR FACE FROM FISH TO MAN

weight, often gaining or losing as much as 15 or 20 pounds
in a short space of time. Those of the linear type on the
contrary do not experience rapid weight changes but main-
tain a very constant weight, and may during the twenty
years from about nineteen to thirty-nine vary a small
number of pounds. The lateral type arrives at puberty
a little late and is slow differentiating, the larynx of the
male does not develop so suddenly as in the linear type and
does not usually grow so large. The voice is thus high
or tenor instead of bass. When men are under thirty
years old the heaviest bass voices are almost always found
among the thin linear individuals and these are very rarely
tenors. The finest tenor voices are those of the round lat-
eral type. Everyone recalls that the fine tenor is a fat
man while the heaviest bass is a tall thin man.

The two types are more clearly expressed in men than
in women since the growth and glandular reactions are
more decided in the male than in the female and are also
freer from physiological disturbances. Many more phy-
sical points of difference and contrast could be cited for
the groups but the above list is sufficient to make the
differences clear.

The balance between these two opposite growth
tendencies is very delicate and during individual
development environmental stimuli may deflect
the results now in one direction and later in the
other, the exact median between the extremes
being seldom realized.

As to the inheritance of individual features, Von
Luschan, Hooton and other anthropologists have
shown that in respect to adult head length and

head breadth, nose length and nose breadth and

236

OUR BEST FEATURES

many similar measurements, the individual tends
to resemble either one parent or the other and not
an average between the two.

The results of crossing the linear and the lateral
types with their opposites are described by Stock-
ard (1921-22, p. 62) as follows:

Again there are persons who do not properly fall into
either type, nor are they typical intermediates, or blends
of the two types. These individuals may possess well
marked fully expressed features of the linear type along
with typically developed lateral features. They may be
dolichocephalic with near-sighted eyes, wide palate arches,
and tenor voices. Combinations that are at once out of
harmony. Such individuals are almost invariably found to
be derived from parents of opposite types, and they are
very common among the offspring of race mixtures.

Environmental influences may tend either to
emphasize or neutralize hereditary tendencies.
According to Stockard, Keith and others, a person
may inherit from his parents a highly active thy-
roid gland which under favorable conditions would
cause a high rate of metabolism and produce
features of the linear type. But owing to disease
or deficiency in iodine this person's thyroid may
be checked in its activity and he may to that
extent acquire lateral features. On the other hand,

another person may tend to inherit a more sluggish

237

OUR FACE FROM FISH TO MAN

thyroid gland, which would give him lateral
features, but owing to some environmental stim-
ulus, such as treatment with thyroxin, his thyroid
gland may be stimulated to greater activity and
to that extent his features may approach the
linear type.

Another complication arises from the circum-
stance that the growing parts themselves show
different degrees of response or receptivity to the
hormones or growth-stimulating substances se-
creted by the ductless glands. In the dachshund,
for example, the bent legs resemble those of the
achondroplastic bulldog, while the long muzzle is
like those of ordinary large hounds (Stockard,
1923, pp. 269, 273). Whatever influence produced
the achondroplastic limbs would have produced a
bulldog-like head, if the growing head itself had
been receptive to it.

One goal of scientific physiognomy would be the
ability to control and regulate the environmental
factors of growth to such an extent that hereditary
defects in the facial make-up could be overcome;
while a eugenic ideal would be to encourage the
increase of strains tending to produce beautiful

faces linked with high intelligence and moral worth.

238

OUR BEST FEATURES

In conclusion, the labors of Keith, Stockard,
Davenport, Bolk and of the endocrinologists are
slowly bringing modern physiognomy toward the
goal of ancient physiognomy, in so far as they
tend to the discovery of correlations between
particular facial characteristics and psychologic
reactions. Thus Stockard, for example, writes as
follows, giving his impressions of various physical
and mental traits associated with the linear and
the lateral growth types:

The basic psychology of an individual is prooably asso-
ciated with his structural type. Two persons of the same
race and region that chance to be of opposite types show
contrasted mental reactions. The lateral type is careful
and painstaking, observing details and valuing them and
making little effort to get at the meaning of things or draw
conclusions until a mass of detail has been accumulated.
This type is emotional and expressive, laughs aloud and
shows impulses and feeling towards things, the eyes easily
fill with tears and the point of view is rarely concealed.
The linear type on the other hand has great difficulty in
accumulating detail or in working a subject out thoroughly.
These individuals have mild respect for details and tend
to draw conclusions and see the meaning of things after
only a hurried survey. They are not emotional and do
not laugh aloud since their reactions are generally under
control and their reflexes are suppressed. They conceal
their impulses and would be ashamed to shed a tear. This
type is self-conscious and nervous, while the lateral type
is not self-conscious and not really nervous in the common
sense of the word. The linear type has great self-control
and among savage tribes the chief is almost always of this

239

OUR FACE FROM FISH TO MAN

type, but among civilized peoples the lateral type with
near sight and emotion are often rulers of great ability.
The lateral type rulers are popular and aware of the details
of the immediate situation but are not apt to perceive the
great principles of the future. So the linear type Presidents
of the United States are honored long after their terms of
service, but are often not popular during office, on the
other hand, lateral type Presidents perchance of equal
ability and equal greatness have been the idols of their
time but leave nothing to be remembered in the future.

The Face of The Future

In the United States the Indians as a whole

have not readily adopted the ways of the white

man and with few exceptions have not been

absorbed into the general population. Hence by

outside political and economic pressure they have

been forced into relatively small reservations where

a great increase in their numbers seems improbable.

Except in very limited regions Indians have

seldom been able to compete for a livelihood with

a more or less antagonistic white population. It

is hardly likely therefore that a thousand years

from now the Indian features will be very common

in the population of the United States as a whole.

The negro population, on the other hand, is much

larger. But the negro is peculiarly liable to

certain fatal diseases and particularly in rural

240

OUR BEST FEATURES

districts infant mortality has hitherto been high.
In the cities where mixed bloods occur in large
number the constant accession of darker features
from the country may more than offset the rela-
tively slow infiltration of white blood. Moreover
the white population is so enormously greater
than the negro and has such great economic and
social advantages and there is such a widespread
and deep antipathy to the marriage of full-blooded
whites and "negroes" of any shade that it seems
highly improbable that the white population will
soon absorb the black population en masse. Hence
it seems unlikely that the average white man's
face a thousand years from now will show much
trace of negroid admixture in the United States as
a whole. In many parts of Africa, on the con-
trary, the whites are so far out-numbered and the
climatic conditions are so unfavorable that it
seems probable that a thousand years from now
the negro, with perhaps some infiltration of white
blood, will still be in the vast majority. Thus we
see at once that the average face of the future in
any given locality will naturally depend first of
all upon the relative increase of one or another

racial type in the general population.

241

OUR FACE FROM FISH TO MAN

As to the changes in the face of the white race,
Sir Arthur Keith has adduced evidence tending to
show that a thousand years ago the average English-
man had a wider face, a shorter nose, a broader
palatal arch and better teeth than the typical
Englishman of today, who tends toward a narrow
face and a narrow- vaulted dental arch. Keith
ascribes this in part to the coarser diet and outdoor
life of a thousand years ago, which gave the
ductless glands that control growth more chance to
produce better teeth and better dental arches.
Nevertheless there is reason to believe that in spite
of the many unfavorable influences today, espe-
cially in the cities, living conditions are on the
whole more sanitary, as shown by the decreasing
mortality. But while there are better conditions
for producing healthy children, more of the weak-
lings are also kept alive to perpetuate their
troubles. In any event, it is not unlikely that in
the long run eugenic counsels will prevail in the
more enlightened countries of the world, at least
to a noticeable extent.

Possibly the people of those days may extract
all their teeth before they begin to give trouble,

or they may be fed with endocrine and other

242

OUR BEST FEATURES

extracts to combat the ills that we now suffer.
In any case it seems not improbable that at least
for a long time conscious effort will be directed
toward correcting unbalanced departures from
the types of face that for thousands of years
past have been considered good-looking. From
all this it appears probable that a thousand years
from now the average adult white person's face
will not be profoundly different from what it is
today.

But what of the human face a million years from
now? — a short period compared with its entire
history. If present tendencies continue unchecked
the white people of those days will for the most
part have lost all four of their wisdom teeth so
that their total number of teeth will be twenty-
eight. This will tend to make their jaws some-
what slender. If they no longer eat meat and
vegetables but take prepared extracts as food,
their jaw muscles and jaws may be further weak-
ened. Their brain capacity on the average may
be considerably larger. Even under the operation
of restrictive eugenic principles there may be at
least as great a diversity in normal white faces then

as there is today. While some of those people

243

OUR FACE FROM FISH TO MAN

might look strange to us, others would remind us
at least of certain types we had seen in our own
times.

In short, the only conservative prediction to
make is that the people a million years from now
may be far less unlike ourselves than we had at
first imagined. But as the determination of the
dominant type of human face in the remote future
will depend partly upon unpredictable economic
and political movements and upon the success in
spreading and enforcing eugenic principles, proph-
ecy of any kind is obviously rash.

If, as many geologists suspect, we are now living
in an interglacial period and the continental ice-
sheet again covers the northern parts of Europe
and North America, then a large part of the white
population may be driven to the southern United
States and Mexico, with consequent tendency to
absorb the more or less colored strains of those
regions; but on the other hand, many of the white
race may persist along the southern borders of the
glaciers. Such speculation is only excusable in
order to make the point that prediction of the
distant future is far less reliable than deciphering

the remote past.

244

OUR BEST FEATURES

Looking Backward

The mobile mask in front of men's brains began
to attract our attention when we were babies and
continues to fascinate us as long as we live.

Its signals have vital meanings to us: we vari-
ously respect, admire, love, hate or are bored by it.

But we cannot escape it. It dominates litera-
ture and with its mystical symbolism it broods
over religion.

Let Science interrogate the sphinx, let her expose
the intricate and delicate mechanism by which
the mask is operated, let her even show that the
human face, with all its charms, is but the end of
a long series of useful improvements upon simple
beginnings.

Yet the transformation of the face from fish to
man will lose none of its wonder.

Our hearts will still move to the flashing glances
of youth; nor will we cherish less the serene,
beloved countenance of old age.

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260

INDEX

Acanthias, labyrinth of, Fig. 104,
205

Achondroplastic dwarf, nose of,
169, 171; development of
skull in, 230

Acorn-worm (Balanoglossus),
theory of relation to ancestors
of vertebrates, 93; larva of
(Tornaria), Fig. 55, 93

Acromegaly, causes and effects of,
171, 231

Adapidae, feet compared with
those of lemur, 54

Adapts, skull of, Fig. 53, 85

African pygmy, nose of, 164, Fig.
89, facing 170

Alar cartilages, of mammalian
nose, 167; growth power of,
170

Alligator, labyrinth of, Fig. 104,
205; ear of the, 207

Alligator-gar, resemblance to De-
vonian ganoids, 23

Allis, Edward Phelps, Jr., head of
shark figured by, 13

Amblystoma punctatum, embryo
of, Fig. 14, 26

Armenian, nose of, Fig. 89, 170

Amphibia, in coal-beds of Great
Britain, 27; restoration of
Eogyrinus, Fig. 15, 28; Wat-
son's studies of early, 28;
disappearance of bony plates
over gill-chamber, 29, Fig. 17,
30, 89, 114; middle ear of
earliest, 29; lower jaw of, 29;
teeth of, 31; teeth similar to
those of lobe-finned ganoids,
81; enlargement of para-
sphenoid, 31; breeding habits
of, 32; development of, 32;
period of dominance of, Fig.
25, 46; man's debt to, 89;
primary upper jaw becomes
attached to skull, 104, Fig. 62,

105; covering of primary jaws
in early, 106; skull compared
with that of crossopt, 107,
Fig. 63, 108; close relatives of
osteolepid crossopts, 114;
elimination of internal gills
in adult stage, 114; feeding
habits of, 114; unspecialized,
nearest to line of ascent to
man, 115; respiration of, 118,
158; naso-buccal channel of,
122; tongue of, 123; first true
ear in, 207; section of head of,
Fig. 106, 208; otic notch of,
209; stapes of, 216; tym-
panum of, 216, 217; Jacob-
son's organ in, 158

Amphioxus, entire animal and
transverse section of, Fig.
54, 92; as descendant of
ancestral stock of vertebrates,
93; ingestion in, 95; "ciliated
groove" of pharynx, 98;
mouth of, 129; light cells of,
Fig. 96, 183; spinal cord
(section), Fig. 96, 183

"Ampullae" of shark, Fig. 6, 13,
16, 204, 206

Anaspida, Fig. 4, 11, 96

Andrews, Roy C, discovery of
Cretaceous mammals by, 51

Angular bone, evolution of, Fig.
52, 82; of Trimerorhachis, Fig.
64, 111; of Megalichthys, Fig.
64, 111; of mammal-like
reptiles, 218

Animalcule, slipper (Paramoe-
cium), Fig. 1, 5

Anteater, Spiny (Echidna), mouth
of, 131

Anthropoid, human dentition de-
rived from that of, 57;
development of the eye in, 65;
face influenced by erect
posture of, 66; date of man's

261

INDEX

Anthropoid — (Continued)

separation from primitive,
74; genesis of temporal bone
in, 88; lips of, 133; incisors of,
138, 139; affinities of Piltdown
canine tooth to that of, 141;
difference between human and
anthropoid dentition, 141;
muzzle of fcetus, 142; foetal
muzzle compared with that of
man, 143; palatal arch of,
143; premolars of, 144; dental
formula of man and of, 145;
type of milk teeth ancestral
to that of man, 149; com-
parison of molar teeth with
those of man, 146, 149; nasal
chambers of, 161; rate of
growth of nasal septum, 167;
human eye compared with
that of, 195; orbital axes of,
196, Fig. 35, 58; external ears
of, 214

Antihelix, development of, 212

Antra, of nasal chamber, 162

Arachnids, theory of vertebrates
derived from, 7

Arboreal life, all primates passed
through stage of, 54; favored
development of eye, 55; man
bears traces of, 63; skull
changes in pro-anthropoids
brought about by, 91

Archseozoic era, origin of plant life
in, 27

"Arches, visceral," 102

Arctocebus, top view of skull, Fig.
35, 58

Aristotle, on physiognomy, 220,
222

Armadillo, foetal, Fig. 114, 221

Articular bone, development of,
112; of Megalichthys, Fig. 64,
111; of T rimer orhachis, Fig.
64, 111; of turtle embryo,
Fig. 64, 111

Arthropods, theory of vertebrates
derived from branch of, 7;
eyes of, 182

Asia, as home of early mammals,
52

Auditory ossicles, of human ear,
202; Fig. 103, 203; Fig. Ill,
216; origin of, Fig. 113, 218;
of foetal Perameles, Fig. 113,

218; of Cynognathus, Fig. 113,
218; innervation of muscles of,
219; of foetal armadillo. Fig.
114, 221; of fcetal hedgehog,
Fig. 115, 221; of human
embryo, Fig. 115, 221

Auricularia, (larva of sea-
cucumber), Fig. 55, 93

Australian aboriginal, skull of
(under side), Fig. 53, 85;
lower molar of, Fig. 80, 151;
nose of, 169

Australopithecus, skull, side view,
Fig. 42, 68; Fig. 46, 72; brain
of, 72; restoration of, Fig. 47,
73

Autostylic attachment, of primary
upper jaw to skull, Fig. 62,
105

Balance, the sense of, 202
Balanoglossus, theory of relation

to ancestors of vertebrates,

93; larva of (Tornaria), Fig.

55, 93
Bandicoot, See Perameles
Baphetes, under side of skull of,

Fig. 53, 85, Fig. 63, 108
Bass, striped, braincase of, Fig.

10, 22
"Becheraugen," of Amphioxus,

Fig. 96, 183
Behavioristic method of study of

physiognomy, 224
Behring Straits, as land-bridge

for early mammals, 52
Bell, Sir Charles, "Essay on the

Anatomy of Expression,"

222
Bichir (Polypterus), 24; embryo of,

Fig. 14, 26
Biconjugate, eyes of man and

apes, 67, 189; movement not

attained by lower primates,

198
Bilateral symmetry, supersedes

radial symmetry, 6
Binocular, eyes of man and apes,

67; vision in man, 189; not

possible in Notharctus, 196;

established in Old World

monkeys and anthropoid

apes, 196
Bipinnaria, larva of starfish, Fig.

55, 93

262

INDEX

Birds, inconspicuous during Age of
Reptiles, 45; period of dom-
inance of, Fig. 25, 46; naso-
buccal channel of, 122

Bloodhound, acromegaly in, 231

Bone-cell, in cross-section of skull
of fossil ganoid, Fig. 9, 20; as
basic element of skull, 21

Bony mask, in Labidosaurus, Fig.
23, 42; sunk beneath skin in
mammals, 43

Brachiation, and quickness of
vision, 198; and biconjugate
movement of eyes, 198

Branchiostegals, elimination of,
114

Brain, rudimentary, of flatworms,
6, Fig. 2, facing 6; of sand-
flea, Fig. 2, facing 6; of
annelid worms, 6; forebrain
of shark, 14; of the tarsier,
53; progressive series in evolu-
tion of primate, 63; primates
characterized by enlargement
of, 64; of chimpanzee, 66; of
Australopithecus, 72 ; skull
changes consequent upon en-
largement of, 87; enlargement
of, in pro-anthropoids, 91;
forebrain as olfactory center,
156; fcetal growth of, its
effect on skull shape, 170; as
derived from ectoderm, 179;
eyes of vertebrates as out-
growths of forebrain, 179;
origin of pineal and parapineal
organs in tract that became
brain tube, 186; visual cortex
of, 191; oculomotor nerves of,
in chimpanzee and man, 198

Braincase, of shark, Fig. 7, 17;
of fish, Fig. 10, 22; as thrust-
block, 22; evolution of pri-
mate, 63; bony crest on base
of, of Scymnognathus, 117

Brain tube, relation of primitive
eyes to, 186

Branchial arches, of shark, Fig. 7,
17; constrictors of, Fig. 8,
18; as origin of larynx, tonsils,
thyroid and thymus glands,
126

Branchial chamber, loss of bones
covering, 89

Branchial skeleton, of man com-

pared with that of other
vertebrates, 128

Broili, F., contributions to palae-
ontology, 86

Broom, R., contributions to palae-
ontology, 86

Brown, Barnum, discovery of
Eodelphis by, 47

Bryant, W. L., contributions to
palaeontology, 86

Bulldog, as abnormal animal type,
230

Bursa (meniscus), origin of, 38,
39; Fig. 22, 38

Calamoichthys, 24

Calcium carbonate, in skeleton of
shark, 23

Canals, semicircular, see Semi-
circular canals

Canine teeth, human, origin of,
90; of primitive man, 76;
of human ancestor, well devel-
oped, 142; human and an-
thropoid, 141; of Piltdown
man, 141, 143; alignment of,
144; of cynodonts, 116

Caniniform teeth, 115

Captorhinus, skull of, Fig. 53, 85

Carnivorous ancestors of man, 136

Cartilage, alar, of mammalian
nose, 167; growth power of,
170; labial, early form of, 104,
of shark, Figs. 7, 8, 17, 18;
Meckel's, see Meckel's carti-
lage; median, of nose, origin
of, 167; oral, of sharks and
embryo vertebrates, 102;
palatoquadrate, of primary
upper jaw, 102

Cartilaginous skeleton, of head of
shark, Fig. 7, 17

Caruncula, of human eye, Fig. 101,
194

Chapelle aux Saints, La, skull of,
see Man, Neanderthal

Cheek arch, of Scymnognathus
and Ictidopsis, 35, 36

Cheek bone, human, foreshadowed
in Mycterosaurus, 34

Cheeks, embryonic development
of the, 166

Ceratohyal, of the shark, 18

Cebus, face of, Fig. 34, facing
56

263

INDEX

Cephalaspis, Fig. 4, 11; mouth of,
Fig. 57, 96

Cephalaspid ostracoderms, Stensio
on, 94

Cephalopods, eyes of, 178, 179;
development of eye in, Fig.
95, 181

Catarrhine monkeys, see Monkeys,
catarrhine

Catablema, ocellus of, Fig. 91, 175

Chimpanzee, facial expression of,
Fig. 116, facing 222; female
and male, Fig. 40, facing 65;
female with young, Fig. 39,
facing 64; brain of, compared
with that of Notharctus and
of man, 65, 66; external ear
of, Fig. 110, 213, 214; face of,
compared with that of early
man, 76; hands of, 198;
palatal arch of, Fig. 74, 140;
incisors of, 138; iris of, 199;
jaw muscles of, Fig. 61, 103;
lacrymal bone of, 200; lower
jaw of, Fig. 45, 71; molar of,
Fig. 79, 150; muzzle of, 142;
nasal meati and sinuses of,
161; oculomotor nerves of,
198; protrusile lips of old,
Fig. 70, 132; skull of, 65
(young), Fig. 102, 197; (fe-
male), Fig. 36, 59; (top view),
Fig. 35, 58; Fig. 43, 69, (front
view), Fig. 44, 70, (under
side), Fig. 53, 85; tongue of,
123

"Chimpanzee type" of human
ear, Fig. 110, 213

Chin, effect of development of
tongue on, 126; of early man,
76

Chlamydoselachus, face of, Fig. 5,
facing 12; instruments of pre-
cision in head of, Fig. 6, 13;
jaw muscles of, Fig. 61, 103;
development of teeth of, 109

Choanse, in palate of lion pup,
Fig. 66, 121; of lizard, Fig. 66,
121; of human embryo, 120,
Fig. 66, 121

Chondrocranium, its component
parts, 83

Chordate, earliest type of verte-
brate, 10; Amphioxus, most
primitive living, Fig. 54, 92

Choroid, of shark, Fig. 99, 192; of
man, Fig. 100, 193

Choroid layer, lacking in cephal-
opod eye, 180

Cilia, as means of ingestion in
Amphioxus, 95; in ostra-
coderms, 95

Ciliary muscles, of eye of shark,
Fig. 99, 192; of human eye,
Fig. 100, 193

"Ciliated groove" of Amphioxus,
Fig. 54, 92; of pharynx of
larval lamprey, 98

Circumorbital bones, Evolution
of the, Fig. 51, 81

Civilization, its effect upon human
teeth, 149

Clark, W. E., Le Gros, on evolu-
tion of primate brain, 63

Cladoselache, frontispiece

Clinical study of physiognomy,
224

Coal measures, see Carboniferous

Cochlea, human, development of,
Fig. 105, 206; its equivalent
first in amphibia, 206; of
human ear, Fig. 103, 203;
spiral ducts of, Fig. 103, 203

Constrictor muscles of gill arches,
104

Cornea, human, Fig. 100, 193;
in shark and man, 193; of
molluscan eye, development
of, Fig. 95, 181; of shark,
Fig. 99, 192

Coronoid bones, of Megalichthys,
Fig. 64, 111; of Trimeror-
hachis, Fig, 64, 111; of turtle
embryo, Fig. 64, 111

Corti, the organ of, Fig. 103, 203,
204

Cotylosaurian reptiles, see Reptiles

Cranial nerve, seventh, 43

Cretinism, cause and effect of, 171

Criminological study of physiog-
nomy, 225

Cro-Magnon man, see Man, Cro-
Magnon

Crossopterygii, related to Carbon-
iferous amphibia, 114; com-
parison of skull with early
Amphibia, 107, Fig. 63, 108;
composition of skeleton, 23;
characteristics of, 24; living
representatives of, 24; dentary

264

INDEX

Crossopterygii — (Continued)

bone of, 108, 130; maxillae
and premaxillae of, 107, 130;
mouth of, 130; nearest to
direct line of ascent, 26;
origin of teeth of, 109; tooth
structure of, 112, Fig. 18,
following, 30; teeth of, 117;
possibly possessed a lung, 24;
Eusthenopteron (upper Devo-
nian), frontispiece; Fig. 12,
facing 23; skull of, under side,
Fig. 53, 85; Fig. 63, 108;
Megalichthys, lower jaw of,
Fig. 64, 111; Rhizodopsis,
skull of, Fig, 17, 30; Fig. 48,
78; Osteolepis, cross section of
skull, Fig. 9, facing 20;
Polyplocodus, teeth of, Fig.
18, following 30; Polypterus,
jaw muscles of, Fig. 61, 103;
embryo of, Fig. 14, 26

Cruciform pattern of lower molars,
149; Fig. 80, 151

Crustacea, compound eyes of, 178;
mouth-legs of, 6

Crus helicis, development of the,
212

Cusps, characteristic of the cheek-
teeth of mammals, 145

Cyclostomes, as possible descend-
ants of ostracoderms, 98, 186;
embryology of the, 186; feed-
ing habits of the, 97, 98;
lamprey, adult, Fig. 59, 97;
lamprey, larval, Fig. 59, 97;
mouth-pouches in, Fig. 56,
94; "tongue" of, 123; tooth-
germs of, (section), Fig. 60,
99

Cynodonts, skulls of, Figs. 48-53,
78-85; dentition of, 115, 116;
secondary palate of, 119;
comparison of molar teeth
with those of man, 145;
middle ear of, Fig. 112, 217

Cynognathus, dentition of, Fig. 77,
147; middle ear of, Fig. 113,
218; jaw muscles of, Fig. 61,
103; skull of, Fig. 53, 85

Darwin, on the origin of mankind,

65
Dawn man, see Eoanthropus daw-

soni

Deltatheridium, D. pretrituber-
culare, skull and head re-
stored, Fig. 29, 50; dentition
of, Fig. 77, 147

Dental formula, of the primates,
Fig. 37, 61; of man and
anthropoids, 145

Dentary bone, its development in
mammal-like reptiles, 108;
evolution in series from fish
to man, Fig. 50, 80; contact
with squamosal in mammals,
87; not dominant in crossopts,
108; covered with skin in
early amphibia and crossopts,
130; crowded out posterior
elements, 36; evolution of,
87; progressive dominance of,
116
of armadillo, foetal, Fig. 114,

221
of crossopts, 110, 130
of Ictidopsis, Fig, 21, 37
of Megalichthys, Fig. 64, 111
of Mycterosaurus, 35
of Scymnognathus, 36; Fig. 21,37
of Thylacinus, 36; Fig. 21, 37
of Trimerorhachis, Fig. 64, 111
of turtle, embryo, Fig. 64, 111

Denticles, constitution of shagreen,
100; in skin of ostracoderms,
117

Dentition, evolution of human,
Fi_g._ 77, 147; Fig. 78, 148;
origin of human, 90; reduced
to two sets in cynodonts, 116

Dermal plates (prevomers) of
Devonian crossopts, 109

"Derm-bones," development of,
21; of fossil crossopts, 112

Dermocranium derived from skin,
21; its component parts, 83

Dermo-supraoccipital bone, evolu-
tion of, Fig. 49, 79

Development and growth, Stock-
ard's studies of, 172

Development of the human face,
Fig. 86, 165; Fig. 87, 166

Diadectes (Permo-Carboniferous),
skull of, Fig. 62, 105

Diademodon, dentition of, Fig. 77,
147

Diaphragm, its origin and func-
tion, 41; Sir Arthur Keith on
the primate d., 63

265

INDEX

Didelphodus, dentition of, Fig. 77,
147

Didelphys, Fig. 26, facing 46; jaw
muscles of, Fig. 61, 103; skull
of, Fig. 28, 49; skull compared
with Eodelphis, Fig. 27, 48

Diet, changes in diet of primitive
man, 75; probable carnivor-
ous diet of man's ancestors,
152; characters of early pri-
mates adapted to, 67; of pre-
vertebrates, 95; later dietary
habits of man, 70

Dinaric type of nose, Fig. 89,
facing 170

Dipnoi, modern survivors of, 24;
removed from main line of
ascent, 25; embryonic devel-
opment of, 25; nose of, 157; re-
spiration of, 122,157; Dipterus
(Devonian), Fig. 13, facing
24

Dipterus (Devonian), Fig. 13,
facing 24

Disharmonic types of human face,
237

Dogs, acromegaly in, 231; ateleosis
in, 231

Dryopithecus, dentition of, Fig. 78,
148; derivation of human
dentition from, 58; lower jaw
of, Fig. 45, 71; D. cautleyi,
premolars, lower front, Fig.
75, 144; molars, lower, Fig.
79, 150; D. fontani, premolars
of, Fig. 75, 144; molars of,
Fig. 79, 150; D.fricka, molars
of, Fig. 41, facing 66, Fig. 79,
150; D. rhenanus, molars of,
Fig. 38, 62; comparison of
upper molars with human,
149

"Dryopithecus pattern," 149, Fig.
41, facing 66; in teeth of
anthropoids, Fig. 79, 150;
in teeth of man, Fig. 80, 151

Duchenne, G. B., his study of
physiognomy, 223

Dwarf, achondroplastic, nose of,
169; skull of, 230

Ear, evolution of the primate, 63;
evolution of auditory ossicles,
215, Fig. 115, 221; innerva-

tion of the muscles of, 219;

movement of, 133
External ear, of antelope, 211

of bat, 211

of chimpanzee, Fig. 110, 213

of Echidna, 210

of elephant, 211

of gibbon (Hylobates), Fig.
110, 213

of gorilla, Fig. 110, 213

of lemur (Lemur catta), 212

of lemuroid (Nycticebus) , Fig.
110, 213

of macaque, foetal, Fig. 109,
212

of mammals, 211

of monkeys, 212

of primates, lower, 57

of orang, Fig. 110, 213

of whale, 211

origin of, Fig. 108, 211;
development of, 211; aid in
development of man, 202;
types of mammalian, 211;
function of human, 202;
approach to monkey type
of fcetal human, 214;
"chimpanzee type" of hu-
man, Fig. 110, 213; re-
semblance of human and
anthropoid, 214
Inner ear

of alligator, Fig. 104, 205, 207

of frog, Fig. 106, 208

of ganoid (Lepidosteus), Fig.
104, 205

of man, Fig. 103, 203, Fig.
104, 205, Fig. 105, 206

of rabbit, Fig. 104, 205

of reptile, primitive (Hat-
teria), Fig. 104, 205; see also
Sphenodon

of shark (Acanthias), Fig.
104, 205

derivation from ectoderm of,
204; components of, 202,
204; functions of, Fig. 103,
203, 204; evolution of, fish
to man, Fig. 104, 205
Middle ear

of ancient and modern Am-
phibia, 29

of frog, 207; Fig. 106, 208

of mammal-like reptiles, Figs.
112, 113, 217, 218

INDEX

Ear — (Continued)

Middle Ear — (Continued)

of foetal mammal, Fig. 113,

218
of man. Fig. Ill, 216
components of, 202; function
of, 202; communication
with throat of, 208
Ear muscles, reduced in man, 215
Ear drum, see Tympanum
Echidna, external ear of, 210; head
of, Fig. 23, 42; mouth of, 131
Echinodermata, Auricularia, larva
of sea-cucumber, Fig. 55, 93;
Bipinnaria, larva of starfish,
Fig. 55, 93
Ectoderm, derivation of brain
from, 179; of mouth from, 94;
of mouth-pouches from, Fig.
56, 94; of inner ear from, 204;
origin of eyes of jellyfish in,
174; specialization of cells of,
157
Egg cell, complexity of the fertil-
ized, 157
Egyptian, upper incisor of old,

Fig. 72, 137
Ehringsdorf man, see Man, Nean-
derthal
Elasmobranchs, see Sharks, Rays,

etc.
Embryo, Jacobson's organ in,
Fig. 82, 159; muzzle of, 142
nose of, 162, Fig. 65, 120
palatal region of, Fig. 66, 121
teeth of, 134, Fig. 71, 135
gill-slits of, 127, Fig. 69, 127
fish-like stage of, 122; tongue
and larynx of, 126
of Amblystoma punctatum, Fig.

14, 26
of macaque, Fig. 108, 211
of man, Fig. 108, 211
of Perameles, 38, Fig. 22, 38
of Polypterus, Fig. 14, 26
of rabbit, Fig. 56, 94
of sturgeon, Fig. 107, 209
of turtle, Fig. 64, 111
of vertebrates, Fig. 56, 94
Embryonic development
of cyclostomes, 186
of Polypterus, 24
of Neoceratodus, 25
Embryology, its evidence on origin
of vertebrate eye, 186

Endocrine glands, as producers of
hormones, 171

Endocranium, derived from carti-
lage, 21

Eoanthropus dawsoni, jaw and
teeth ape-like, 72; lower jaw
of. Fig. 37, 61; lower jaw of,
Fig. 45, 71; left lower molars
of, Fig. 38, 62; left lower
molars of, Fig. 41, facing 66;
skull, side view, Fig. 42, 68

Eocene, mammalian remains from,
53; early placental mammals
in, 52; development of eye in
primates of, 55; European
Adapidse from, 54

Eodelphis (Cretaceous), restora-
tion of face of, frontispiece;
skull compared with Didel-
phis, Fig. 27, 48; skull
compared with Notharctus,
55; skull of, Fig. 48, 78

Eogyrinus (Lower Carboniferous),
Fig. 15, 28; restoration of face
of, frontispiece

Epipterygoid bone, of Diadectes,
Fig. 62, 105

Epipterygoid process, of foetal
salamander, Fig. 62, 105

Epithelial cells, differentiation of,
156

Epithelium, derivation of primi-
tive eye from, 176; as origin
of parts of the vertebrate
eye, 179

Erinaceus, auditory ossicles of
embryo, Fig. 115, 221

Eryops, jaw muscles of, Fig. 61,
103

Ethmoid sinus, 162; its connection
with nasal meati, Fig. 85, 163

Ethmoidal cartilage, ossification
of, 199

Eurypterids, derivation of verte-
brates from forms related to,
182

Eustachian tube, of frog, 207;
Fig, 106, 208; of man, Fig.
Ill, 216; in human embryo,
162

Eusthenopteron (Devonian), Fig.
12, facing 23; face of, frontis-
piece; skull of, under side,
Fig. 53, 85; skull of, under
side, Fig. 63, 108

267

INDEX

Evolution, proceeds by loss of
superfluous parts, 114; of
human face, Sir Arthur Keith
on, 120; of primates, diver-
gent, 57; of the circumor-
bital bones, Fig. 51, 81; of
human dentition, Fig. 77,
147; also Fig. 78, 148; of the
human jaw bones, Fig. 50,
80; of human jaw muscles,
Fig. 61, 103; of human skull
roof, Fig. 49, 79; of human
skull, under side, Fig. 53, 85;
of the temporo-mandibular
series, Fig. 52, 82; of the
vertebrate eye, Fig. 97, 185

Eyes, beginnings of, Fig. 91, 175;
biconjugate movement and
the oculomotor nerves, 198;
ciliary muscles of, 193; cir-
cumorbital bones, evolution
of the, 88; Fig. 51, 81; clear-
ness of vision and the brach-
iating habit, 198; correlation
of vision with smell, 156; as
directional organs, 178, 200;
dorsal eyes, Fig. 97, 185, 187,
200; elements of primitive,
and their functions, 175;
choroid of vertebrate, 188;
evolution of vertebrate, Fig.
97, 185; evidence of em-
bryology on origin of verte-
brate, 186; function of paired,
177; Plate cited on paired
eyes of vertebrates, 178;
paired eyes essentially an
outgrowth of brain, 179;
meagre fossil evidence of
origin of vertebrate paired
eyes, 184; vertebrate and
invertebrate, compared, 178,
180, 181; summary of deve-
lopment of vertebrate, 200;
human, as a camera, 189;
development of human eyes
favored by arboreal life, 55,
90; function of human, 173;
comparison of human, and
shark, 192; comparison of
human, and anthropoid, 195;
position of, inherited from
pro-anthropoid stock, 196;
pineal and parapineal, Fig.
97, 185, 200; caruncula of

human, 194; fundus oculi of
human, 199; horizontal sec-
tion of, Fig. 100, 193; iris of
human and anthropoid, 198;
lacrymal glands and canals
of human, Fig. 101, 194;
macula lutea of human and
anthropoid, 199; muscles of
human, Fig. 98, 190, 191;

of cephalopod mollusca, devel-
opment of Fig. 95, 181

of flat worm (Planaria), Fig. 92,
177, Fig. 2, facing 6

of jellyfish (Catablema), Fig. 91,
175

of jellyfish (Sarsia), Fig. 91, 175

of Ampkioxus, Fig. 96, 183

of deep-sea cephalopods, 178

of Crustacea and insects, 178

of flatworms, 6, 176

of Galago, 60

of invertebrates, 174

of advanced lemuroids, 60

of Limulus, 182

of higher mollusca, 178

of Nautilus, 181

of Notharctus, position in, Fig.
35, 196

of Pecten, 178

of Planaria, as directional
organs, Fig. 93, 178

of Planaria, section. Fig. 92, 177

of pre-chor dates, 186

of primates, development of,
65; progressive declination of
the, Fig. 36, 59

of protista, 174

of sand-flea (Orchestia) , Fig. 2,
facing 6

of scorpion, 182

of shark (Chlamydoselachus
anguineus), Fig. 6, 13, 15

of shark, horizontal section,
Fig. 99, 192

of shark nearer to human than
to invertebrate, 191

of squid, section of, Fig. 94, 179

of Tarsius, Fig. 31, facing 53,
60
Eye stalks, formation of the, Fig.

97, 185
Eyeball, muscles of the human,
Fig. 98, 190; muscles of the,
of shark, Fig. 6, 13, 15
Eyelids, of man, 194; of Sepia, 180

268

INDEX

Face, as index of character, 220;
changes in arboreal pro-
anthropoids, 91; changes in
primitive man, 76; embryonic
development in mammals,
166; extremes in form and
color of, Fig. 90, facing 172;
primary functions of the, 3;
shape of anthropoid f. con-
ditioned by erect posture,
64, 66; Mongolian type, 170;
human, of same elements as in
gorilla, 91; Sir Arthur Keith
on evolution of, 120; three
stages in evolution of, 122
Stockard's classification of
the, 232
of young chimpanzee, Fig. 116

facing 222
of chimpanzee, Figs. 39, 40

facing 64, 65, 66, 76
of lemur (Lemur variegatus)

Fig. 34, facing 56
of man, see Man, face of
of catarrhine monkey (Lasio
pyga pygerythrus), Fig. 34
facing 56
of platyrrhine monkey (Cebus
capucinus), Fig. 34, facing 56
of shark Chlamydoselachus, Fig.
5, facing 12
Facial armor of Osteolepis, Fig. 11,

facing 22
Facial expression, methods for

the study of, 223-5
Facial muscles,

of Echidna, Fig. 23, 42
of gorilla, Fig. 23, 42
of Labidosaurus, Fig. 23, 42
of man, Fig. 23, 42
of Sphenodon, Fig. 23, 42
Facial nerve, chief branches of,
Fig. 24, 44; original territory
of the, 132
Features, inheritance of individ-
ual, 236
Feeding habits of some Amphibia,

114
Feet, correlated use of, in Pri-
mates, 64; evolution of pri-
mate, 63
Fishes, lobe-finned, ancestral to
land vertebrates, 26; com-
parison of skull with that of
amphibian, 29; theories of

origin of, 7, 8, 92, 93; ears of
primitive, 204; jaws of, prim-
ary, 104; jaw muscles and
jaws of, 104-6; lateral line
organs of, 206; man owes
ground-plan of face to early,
89; methods of ingestion of,
104; resemblance of human
embryo to, 122; shoulder
girdle of, compared with that
of early amphibia, 28
Crossopterygii

bony plates on primary jaws
of, 106; Fig. 12, facing 23;
chemical composition of
skeletion of, 23; structure of
teeth, 112; Fig. 18, following
30

Eusthenopteron, Fig. 12, fac-
ing 23; face of, frontispiece ;
skull of, under side, Fig.
53, 85; skull of, under side,
Fig. 63, 108
Osteolepis, skull of, top view,
Fig. 11, facing 22; cross
section of skull, Fig. 9, fac-
ing 20
Polyplocodus, teeth of, Fig. 18,

following 30
Polypterus, jaw muscles of,
Fig. 61, 103; embryo of,
Fig. 14, 26
Rhizodopsis, skull of, Fig. 17,
30; skull of, side view, Fig.

48, 78; skull, roof of, Fig.

49, 79
Dipnoi (Dipneusti)

Dipterus, the nose of, Fig. 13,
facing 24, 157; respiration
of, 122
Elasmobranchii, see Shark, pas-
sim
Ganoidei, skeleton, composition
of, 23
Flatworm (Planaria), Fig. 2,
facing 6; apparently descend-
ant of jellyfish group, 5;
eyes of the, 176, Fig. 92, 177,
eyes as directional organs
in the, Fig. 93, 178; illustrates
evolution of primitive head,
6, Fig. 2, facing 6
Foot, of tree-grasping type in all

primates, 54
Fore-brain, as olfactory center, 156

269

INDEX

Forests of the Devonian period, 27
"Fossil, living," opossum as a, 47
Fovea anterior, 149; in molar of
Ehringsdorf man, Fig. 80, 151
Fovea posterior, 149
Frog, development of ear in, 207;
Eustachian tube of, 207;
head of, transverse section of,
Fig. 106, 208; stapes of,
216
Frontal bones, 83; become one of
dominant elements in vault
of human skull, 87; evolution
shown in series of ten skulls
from fish to man, Fig. 49, 79;
joint process of frontal and
malar replaces reptilian post-
orbital bones, 90; their rela-
tion to superior maxillary in
mammals, 87; retained from
fish to mammals, 86; sinus of,
161
of chimpanzee, female, Fig. 49,

79
of Didelphys, 50; Fig. 49, 79
of Iclidopsis, Fig. 49, 79
of man, Fig. 49, 79
of Mycterosaurus, Fig. 49, 79
of Notharctus, Fig. 49, 79
of Seymouria, Fig. 49, 79
Frontal sinus, its connections with

nasal meati, Fig. 85, 163
Fundus oculi in man and anthro-
poids, 199

Galago, eye and orbits of, 60

Ganoids, possessed a lung, 24;
skull compared with that of
amphibian, 29, 107; com-
position of skeleton, 23;
mouth of, 130; relation to
human ancestry, 24; hyoid
gill cleft in, 209; teeth of
earliest amphibia similar to
those of, 31

Ganoine, 23; covers bony jaw-
plates of higher fishes and
early amphibia, 106; on max-
illae and premaxillae of early
crossopts, 130; on teeth of
fossil crossopts, 112

Gaupp, E., cited on the origin of
the meniscus, 38

Genetic study of physiognomy,
224

Genioglossus, see Geniohyoglossus
muscle

Geniohyoglossus muscle, of gorilla,
Fig. 67, 124; of man, Fig. 67,
124; Fig. 68, 125, 126

Gibbon (Hylobates) external ear
of, Fig. 110, 213; habit of
climbing upright, 64; hands
of, 198; palatal arch of
female, Fig. 74, 140; skull of,
top view, Fig. 35, 58

Gidley, J. W., on mammalian
teeth from Basal Eocene, 53

Gigantism and acromegaly in
dogs, 231

Gill arches, see Branchial arches

Gill cartilages, folding of, in
shark, 123

Gill chamber, bony covers of the,
23; changes of, from crossopts
to Amphibia, 29

Gill clefts, in embryo sturgeon,
Fig. 107, 209

Gills, internal, eliminated by
Amphibia in adult stage, 114

Gill openings, homologous with
mouth-pouches, 94

Gill region

of Cephalaspis (restored by

Stensio), Fig. 57, 95
of Kiceraspis, Fig. 57, 95

Gill slits, in human embryo of
third week, Fig. 69, 126, 127

Glands, endocrine, as producers
of "hormones," 171; hypo-
physis, 230; hypophysis-
pituitary complex, 231; lacry-
mal, human, 194; Meibomian,
in human eyelids, 194; pineal
and parapineal, 186, 200;
pituitary, effect of diseased,
171; salivary, of man and
apes, 129; sebaceous, origin
and function of, 41; sudori-
parous, origin and function
of, 41; thyroid, and gigan-
tism, 231; effects of deficient,
171; effects of deranged, 237;
effect on growth of face,
232

"Goblet eye" of flatworm, section
of, Fig. 92, 177; of jellyfish
(Sarsia), Fig. 91, 175

Goniale, of armadillo, foetal, Fig.
114, 221; of hedgehog (Erin-

270

INDEX

Goniale — {Continued)

aceus) foetal, Fig. 115, 221; of

human embryo, Fig. 115, 221

Gorgonopsian reptiles, see Reptiles

Gorilla, external ear of, Fig. 110,

213,214; facial muscles of, Fig.

23, 42; facial nerve of, Fig.

24, 44; hands of, 198; head,
longitudinal section, Fig. 67,
124; lacrymal bone, 200;
lachrymal bone of foetal, 199;
nose of, 164, 170; nose of,
foetal, Fig. 84, 161; palatal
arch of male, Fig. 74, 140;
nasal meati and sinuses of,
161; skull compared with
Piltdown, 143; skull of young
g., front view, Fig. 102, 197;
teeth foreshadow "shovel
shaped" incisors, 138; teeth,
lower molar, Fig. 79, 150;
teeth, canine, resemblance to
Piltdown, 141; central incisors
of young, Fig. 72, 137; milk
teeth of young, Fig. 76, 146;
tongue of young, 123

Gregory, William K., his con-
tributions to palaeontology,
86; places separation of man
and anthropoids in Lower
Miocene, 74; on hind-feet of
primates, 54; "Origin and
Evolution of the Human
Dentition," 146

Gregory, William K., and Milo
Hellman, 146; "The Denti-
tion of Dryopithecus and the
Origin of Man," 146

Gregory, William K., and
Simpson, G. G., describe
Cretaceous mammals, 51

Growth, glandular factors affect-
ing, 237; mechanism of, 172;
stimulation of, by "hor-
mones," 171; types of, in
man, Fig. 117, 232

Gular plates, elimination of, Fig.
17, 30; also 114

Hagfishes (Cyclostomata), com-
pared with ostracoderms, 97;
ostracoderms ancestral to,
10; tongue of, 123

Hair, origin and function of, 41;
possibly possessed by mam-

mal-like reptiles of Trias, 42
Hands, correlated use of eyes,

hands and feet, by primates,

64; evolution of primate, 63;

progressive changes of, 198
Hatteria, labyrinth of, Fig. 104,

205
Hatteria, see also Spkenodon
Haughton, S. H., his contributions

to palaeontology, 86
Head, evolution of primitive, Fig.

2, facing 6; inheritance of

head shape, 236; nature and

function of, 12;
of arachnids, 7
of Australopithecus, restored.

Fig. 47, facing 73
of Deltatkeridium, restored, Fig.

29, 50
of Echidna, Fig. 23, 42
of flat worm (Planaria), Fig. 2,

facing 6
of frog, transverse section, Fig.

106, 208
of gorilla, young, longitudinal

section, Fig. 67, 124
of Labidosaurus, Fig. 23, 42
of lamprey, larval, longitudinal

section, Fig. 56, 94
of man, longitudinal section,

Fig. 67, 124
of man, embryo, third week,

Fig. 69, 127
of ostracoderms, 11
of rabbit, longitudinal section,

Fig. 56, 94
of sand-flea (Orchestia), Fig. 2,

facing 6
of shark, cartilaginous skeleton

of, Fig. 7, 17
of shark, dissection of, Fig. 81,

155
of shark (Chlamydoselachus),

Fig. 5, facing 12
of shark (Chlamydoselachus),

diagram, Fig. 6, 13
of Sphenodon, Fig. 23, 42
of Zalambdalestes lechei, re-
stored, Fig. 29, 50
Hearing, the mechanics of, 204
Hedgehog (Erinaceus) foetal,

auditory ossicles of, Fig. 115,

221
Heidelberg man (Homo heidel-

bergensis), chin of, 72; lower

271

INDEX

Heidelberg man — (Continued)

jaw of, Fig. 37, 61; Fig. 45,
71; lower molar of, Fig. 80,
151; teeth of, 143

Helix, development of, 212

Hellman, Milo and William K.
Gregory, "The Dentition of
Dryopithecus and the Origin
of Man," 146

Herbivorous vertebrates, could
not have given rise to carniv-
orous forms, 101

Heredity, the shape of the head,
236; and the shape of the
nose, 172

Hesse, on the primitive eye, 176

Hindu, lower molar of, Fig. 80, 151

Hittite, type of nose, 169; Fig. 89,
facing 170

Homo heidelbergensis (Heidelberg
man), chin of, 72; lower jaw
of, Fig. 37, 61; Fig. 45, 71;
lower molar of, Fig. 80, 151;
teeth of, 143

Homo neanderthalensis, lower jaw
of, Fig. 45, 71; left upper and
lower molars of, Fig. 38, 62

Homo neanderthalensis (La Chap-
elle aux Saints), skull of, side
view, Fig. 42, 68; skull of,
top view, Fig. 43, 69; skull of,
front view, Fig. 44, 70

Homo neanderthalensis (Ehrings-
dorf), central incisors of, Fig.
72, 137; lower jaw of, Fig. 45,
71; lower molar of, Fig. 80,
151; lower front premolars of,
Fig. 75, 144

Homo neanderthalensis (Le Mous-
tier), dentition of, Fig. 78,
148; characters of teeth of,
Fig, 45, 71, 72; central
incisors of, Fig. 72, 137;
lower molar of, Fig. 80, 151;
palatal arch of, Fig. 74, 140

Homo sapiens, see Man

Hooton, Earnest A., his work on
inheritance, 236

Hormones, the function of, 171

Hottentot, male, the face of, Fig.
90, facing 172

Hrdlicka, Ales, on incisors of
anthropoids and monkeys, 138

Huber, Ernst, on facial muscles,
44, 132

Human characters, point at which

primates assumed, 64
Human Dentition, Evolution of

the, Fig. 77, 147; Fig. 78,

148
Human Ear, Evolution of the.

Fig. 104, 205
Human Circumorbital Bones,

Evolution of the, Fig. 51,

81
Human Temporomandibular

Series, Evolution of, Fig. 52,

82
Human Face, Development of the,

Fig. 86, 165; Fig. 87, 166
Stockard's classification of the,

232
Human Jawbones, Evolution of

the, Fig. 50, 80
Jaw muscles, Evolution of the,

Fig. 61, 103
Nose, Embryonic stages of the.

Fig. 65, 120
Skull roof, Evolution of the,

Fig. 49, 79
Human types, abnormal, studies

of, 229
Humor, vitreous, 188
Hunter, John I., on evolution of

primate brain, 63, 198
Huxley, T. H., his views con-
firmed, 51
Hydroids, effect of ultra-violet

rays on, 174
Hylobates, external ear of, Fig.

110, 213; skull of, top view,

Fig. 35, 58; male, palatal

arch of, Fig. 74, 140
Hyoid arch, of man homologous

with that of primates, 128;

primary upper jaw suspended

from, 104; stapes derived

from, 215; cartilage, of

Echidna, 210; gill pouch, ear

derived from, 208
Hyoid, of shark, Fig. 7, 17
Hyomandibular cartilage, of

shark, Fig. 62, 105; Fig. 7,

17; Fig. 8, 18
Hyostylic attachment, of jaw in

shark, Fig. 62, 105
Hypophysis of larval lamprey,

Fig. 56, 94
Hypophysis-pituitary complex, in

acromegaly, 231

272

INDEX

Jctidopsis, dentary of, Fig. 21, 37;
restoration of face of, frontis-
piece; skull of, Fig. 20, 35;
Fig, 28, 49; Fig. 48, 78

Incisors, of anthropoids and
monkeys, 138; mammillae on,
136; Fig. 72, 137; of chimpan-
zees, 138; of cynodonts, Fig.
50, 80, 116; central, of gorilla,
Fig, 72, 137; of Neanderthal
man (Le Moustier), Fig. 72,
137; of Neanderthal man
(Ehringsdorf), Fig. 72, 137
of old Egyptian, Fig. 72, 137
of white boy, Fig. 72, 137
upper central, of man, three
types of, 138; Fig. 73, 139;
"shovel-shaped," of the
Krapina race, Mongolians
and Indians, 138; retreat of
human, 144; of fossil man,
143; origin of, 90

Incus, human embryo shows origin
of, 220
of armadillo, foetal, Fig. 114, 221
of Cynognathus, Fig. 113, 218
of hedgehog (Erinaceus), foetal,

Fig. 115, 221
of man, Fig. Ill, 216
of man, foetal, Fig. 115, 221
of Perameles, foetal, Fig. 113,
218

Indians, "shovel-shaped" incisors
of, 138

Indrodon, left upper molar of,
Fig. 38, 62

Infusoria, effect of ultra-violet
rays on, 174

Inheritance, of individual char-
acters, 236

Insectivores, ancestors of man
were, 52

Insectivorous dentition, traces of,
in early primates, 57

Insects, compound eyes of, 178

Interarticular disc, formation of,
in Perameles, Fig. 22, 38

Interoperculum, elimination of,
Fig. 17, 30, 114

Interorbital space, in advanced
lemuroids, 60

Interparietal bones, retained from
fish to man, 86

Intertemporal bone, its changes
from fish to man, Fig. 49, 79;

loss of, in reptiles, 89; re-
duction of, 88

Invertebrates, well established be-
fore vertebrates, 8; eyes of,
173; eyes compared with ver-
tebrate, 178; eyes of higher,
178

Iris, of man, Fig. 100, 193; of
mollusca, development of,
Fig. 95, 181; of Sepia, 180;
of shark, Fig. 99, 192

Jacobson's organ, description of
158; in man, fcetal, Fig. 65,
120; Fig. 82, 159

Jaw, conclusions from history of
the, 152; elements traced
from earliest Amphibia to
man, 107; evolution of the
bones of the, 87; Evolution
of the Human, Fig. '50,
80; evolution of the primate,
63; mammalian joint of, its
formation, 39; the interartic-
ular disc in (Perameles, foetal),
Fig. 22, 38; its elements
homologous in crossopts and
early Amphibia, 107; laby-
rinthodont method of attach-
ment of teeth in, 112; points
of advancement in crossopt
jaws, 113; prognathous jaws
and shape of nose, 170; Fig.
89, facing 170; primate,
tabular history of, Fig. 37,
61; origin uncertain below
ostracoderms, 101; of dipnoan
fishes, 25; of fossil ganoids,
23; of Osteolepis, Fig. 11,
facing 22; architecture of
"visceral arches," 104; pro-
gressive changes associated
with development of mus-
culature of, 116; of shark
nearer to those of man than
to invertebrate, 102; special-
ized jaws of some Amphibia,
115
Primary, completely masked by
secondary jaws in higher
vertebrates, 104, 106; of
crossopts, 106, 110, 113; of
higher fishes and early Am-
phibia, covered with ganoine-
coated bony plates, 106; of

273

INDEX

Jaw — (Continued)

Primary — (Continued)

shark, 106, Fig. 7, 17; Fig. 8,
18; of primitive sharks, 109;
of lower primates, in relation
to eyes, 60; buds of, in hu-
man embryo, Fig. 69, 127
Primary Upper, elimination of
teeth in, 115; methods of
attachment of, 104, Fig. 62.
105; palatoquadrate cartilage,
102; traces of, in mammalian
embryo, 106; retained teeth
in Amphibia, 115; of Baphetes,
Fig. 63, 108; of Devonian
crossopts, 109; of Eusthenop-
teron, Fig. 63, 108
Primary Lower, coronoid bones
of, in crossopts, 110; develops
into articular bone, 112;
Meckel's cartilage, 102
Secondary, definition and de-
scription, 107; elements of
the, 107; shows unity of
origin of higher vertebrates,
107; in sharks, represented
only by skin, 106
of armadillo, fcetal, relation
of ossicles to, Fig. 114, 221
of crossopts, 109; also 113
of Dryopithecus, section of,

Fig. 45, 71
of Eodelphis, Fig. 27, 48
of Leipsanolestes siegfriedti,

Fig. 37, 61
of man, influenced by size and

function of tongue, 126
of man, longitudinal section,

Fig. 68, 125
of man, Cro-Magnon, section
of, Fig. 45, 71; Ehrings-
dorf, section of, Fig. 45, 71;
Heidelberg, section of, Fig.
45, 71; Neanderthal, section
of, Fig. 45, 71; Piltdown,
Fig. 41, facing 66, 142;
Piltdown, section of, Fig.
45, 71
of Megalichthys, Fig. 64, 111
of monkey, longitudinal sec-
tion, Fig. 68, 125
of Mycterosaurus, 34
of Pelycodus trigonodus, Fig.

37, 61
of Seymouria, 32

of Trimerorhachis, Fig. 64, 111
Jaw muscles

of Chlamydoselachus, Fig. 61,

103; also Fig. 8, 18
of Cynognathus, Fig. 61, 103
of Didelphys, Fig. 61, 103
of Eryops, Fig. 61, 103
of fishes, their evolution, 104
of man, evolution of, Fig. 61,

103
of Notharctus, Fig. 61, 103
of chimpanzee, Fig. 61, 103
of Polypterus, Fig. 61, 103
of Scymnognathus, Fig. 61, 103
of shark, their derivation, 104
Jellyfish, mouth of the, 4, 5; eyes
of, 174; eye of, (Sarsia),
section of. Fig. 91, 175;
Tessera, Fig. 1, 5
Jugal bone (malar), 83; series of
skulls showing evolution of,
Fig. 51, 81; Fig. 53, 85; joint
process of frontal and malar
replaces reptilian postorbital,
90

Karroo (Africa), mammal-like
reptiles of, Fig. 20, 35-36

Keel bone, see Parasphenoid bone

Keith, Sir Arthur, on the develop-
ment of the human ear, 212;
his studies of abnormal
human types, 229; "Mor-
phology and Embryology,"
157; on the primate dia-
phragm, abdomen and pelvic
floor, 63; his study of growth,
237; on the evolution of the
human face, 120; on the hind
feet of primates, 54

Kiaer, J., on ostracoderms, 10

King crab (Limulus), 7

Kinsfolk, Some of Our Earliest,
Fig. 4, 11

Krapina race (Neanderthal),
"shovel shaped" incisors of,
138

Labial cartilages, of shark
(Chlamydoselachus), Fig. 6,
13; Fig. 7, 17; Fig. 8, 18; 130
Labidosaurus, head of, Fig. 23, 42
Labyrinth, embryonic develop-
ment of, 204
of alligator, Fig. 104, 205

274

INDEX

Labyrinth — (Continued)

of ganoid (Lepidosteus) , Fig.

104, 205
of man, 202; Fig. 103, 203,

Fig. 104, 205, Fig. 105, 206
of rabbit, Fig. 104, 205
of reptile (Hatteria) (Sphenodon)

Fig. 104, 205
of shark (Acanthias), Fig. 104,
205

Labyrinthodont, attachment of
teeth, 112; pattern in teeth
of fossil crossopts, Fig. 18,
following 30, 112; teeth of
Devonian fish (Polyplocodus),
Fig. 18, following 30; traces
in teeth of Seymouria, 118

Labyrinthodonts, teeth of the,
113, 115

Lacrymal apparatus of human
eye, Fig. 101, 194

Lacrymal bone, 83, 194; develop-
ment of, 199; relation to
superior maxillary and jugal
in mammals, 87; series of ten
skulls showing evolution of,
Fig. 51, 81; similar in man
and anthropoids, 199; sur-
vives in man, 88

Lacrymal glands and canals in
human eye, 194

Lacrymal sac, in human eye, 194

Lagena, of alligator, Fig. 104,
205

Lampreys (Cyclostomata), ostra-
coderms ancestral to, 10;
compared with ostracoderms,
97; adult, Fig. 59, 97; embry-
ology of, 186; feeding habits
of, 98; mouth of adult, 129;
tongue of, 123; section of
tooth germ of, Fig. 60, 99;
"ciliated groove" of pharynx
(Ammocates stage), 98; longi-
tudinal section of larval, Fig.
59, 97; mouth of larval, 129;
mouth pouches in larval, Fig.
56, 94

Lanarkia, shagreen denticles of,
100; teeth represented by
denticles, 117

Lancelet, see Amphioxus

Laryngeal complex, of man and
other vertebrates, 128

Larynx, in human embryo, 126;

origin in branchial arches,
126

Lasiopyga kolbi, side view of skull,
Fig. 36, 59

Lateral line organs of fishes, 206

Lateral type, in man, Fig. 117,
232; result of crossing with
linear, 237

"Lateral line," of Stockard, Fig.
118, 234

Le Double, his work on lacrymal
bone, 199

Legs, hind, of the tarsier, 53; Fig.
31, facing 53

Leipsanolestes, left lower molar of,
Fig. 38, 62; jaw of, Fig. 37, 61

Lemur, African (Arctocebus) , top
view of skull, Fig. 35, 58

Lemur (Lemur catta), ears of, 212;
face of, 56; Fig. 34, facing 56;
L. variegatus, face of, Fig. 34,
facing 56; olfactory sense of,
196; rhinarium of, 56

Lemuroids, eyes of advanced, 60;
Adapis (Eocene) skull of,
under side, Fig. 53, 85;
Notharctus, skull, side view,
Fig. 36, 59; Notharctus, skull,
top view, Fig. 35, 58; hands
of, 198; orbital axes of, Fig.
35, 58, 196; Nycticebus, ex-
ternal ear of, Fig. 110, 213;
Pelycodus, left upper and
lower molars of, Fig. 38, 62;
jaw of, Fig. 37, 61; Pro-
pithecus, restoration of face
of, frontispiece

Lens, in eye of Sepia, 180; lens, in
development of molluscan
eye, Fig. 95, 181; formation
of the, in vertebrate eye, Fig.
97, 185, 187; in eye of man,
Fig. 100, 193; in eye of shark,
Fig. 99, 192

"Light cells," of the primitive eye,
175, 176; Fig. 91, 175; of Am-
phioxus, Fig. 96, 183

Limulus, 7; eyes of, 182; Patten
derives vertebrates from
relatives of, 92
Lindsay-Johnson, his work on the

fundus oculi, 198
Linear type of human growth,
Fig. 117, 232; results of cross-
ing with lateral, 237

275

INDEX

Lips, embryonic development of
the, 166; origin and evolution
of human, 129; mammalian,
their most distinctive feature,
131; philtrum of, 133; of
anthropoids, 133; of old chim-
panzee, Fig. 70, facing 132; of
Lemur, 56, Fig. 34, facing
56; of catarrh in monkeys,
56, Fig. 34, facing 56; of
platyrrhine monkeys, 56, Fig.
34, facing 56; of lower prim-
ates and man, 133; of Spiny
Ant-eater, 131; uses of pro-
trusile, 133; muscles of, their
importance to newborn mam-
mal, 133, 134

Lizard, palate of, Fig. 66, 121

Lobe-finned fishes (see also Cros-
sopterygii, Fishes), Eusthe-
nopteron, Fig. 12, facing 23,
Fig. 53, 85, Fig. 63, 108;
Osteolepis, Fig. 11, facing 22,
Fig. 9, facing 20; Poly-
plocodus, Fig. 18, following
30; Polypterus, Fig. 14, 26,
Fig. 61, 103; Rhizodopsis,
Fig. 17, 30, Fig. 48, 78, Fig.
49, 79

Lobule, development of the, 212

Locomotion, of primitive man,
changes in, 75; skull changes
related to habits of, 88

Loxomma allmani (Carbonifer-
ous), skull of, Fig. 16, facing
28; teeth of, Fig. 18, following
30

Lung-fishes (Dipnoi), (Dipneusti),
embryonic development of, 25 ;
modern survivors of, 24; the
nose of, 157; Neoceratodus, 25

Luschan, F. v., his work on in-
heritance, 236

Macaque, embryo of, Fig. 108,
211; external ear of, Fig. 109,
212

"Macula lutea," in man and apes,
199

Malar bone (Jugal), series of
skulls showing evolution of,
Fig. 51, 81, 83, Fig. 53, 85;
joint process of frontal and
malar replaces reptilian post-
orbital, 90

Malleus, human embryo shows
origins of, 220
of armadillo, foetal, Fig. 114, 221
of Cynognathus, Fig. 113, 218
of man, Fig. 103, 203
of man, Fig. Ill, 216
of man, foetal, Fig. 115, 221
of Perameles, foetal, Fig. 113, 218
Mammals, appear in large num-
bers at the close of the Age
of Reptiles, 52; their condi-
tion during the Age of
Reptiles, 45; some early m.
believed related to Platypus,
47; body temperature of, 40;
origin of the, 40; period of
dominance of, Fig. 25, 46;
type of primitive, Fig. 27,
48; cusps characteristic of
cheek teeth of, 145; the ear
of, 207, 211; face of, its
embryonic development, 166,
facial muscles of, their origin,
43, 132; Jacobson's organ in
primitive, 158; jaw, embry-
onic traces of primary upper,
106; jaw, upper, of m., Fig.
50, 80, 87; method of respira-
tion, 119; nasal chamber of,
158; palatal regions of, 119,
Fig. 52, 82, Fig. 53, 85; their
forerunners from Mongolia,
51; Fig. 29, 50; early placental
from New Mexico, 52; tongue
of, 123; teeth of triconodont
m., 136
"Mammalian joint," see also In-
terarticular disc, 87, 90; for-
mation of, 39; development of
dentary and squamosal bones
to form, 108, 109
of Ictidopsis, Fig. 21, 37
of Perameles, fcetal, Fig. 22, 38
of Scymnognathus, Fig. 21, 37
of Thylacinus, Fig. 21, 37
Man, Darwin on the origin of, 65;
his debt to the Amphibia, 89;
possibility of his existence
derives from the Amphibia,
32; unspecialized Amphibia
nearest to line of ascent, 115;
relation of ganoids to his
ancestry, 24; nearer to shark
than shark to invertebrates,
14, 102; a hiatus in his

276

INDEX

Man — (Continued)

history in Pliocene, 70; his
ancestors not large ferocious
animals, 20; his ancestors
small, long-snouted, insec-
tivorous - carnivorous mam-
mals, 52; probable carnivor-
ous diet of the earlier an-
cestors of man, 152; om-
nivorous - carnivorous diet
habits later developed, 70;
derived from frugivorous
proto - anthropoids, 69;
changes in diet of primitive
man, 75; gradual modification
of structure of, 84; structural
changes incident to changes
of habit, 75; bears stamp of
arboreal ancestors and later
bipedal adaptation, 63; com-
pared with chimpanzee and
Notharctus, 65; converges in
past to common source with
anthropoids, 74; date of his
separation from early an-
thropoids, 74; several types
of, in early Pleistocene, 73;
period of dominance, Fig. 25,
46; linear and lateral types
of, Fig. 117, 232; some racial
types compared, 76; source
of the amelioration of his
features, 153; m. and primate,
characters of, 67; develop-
ment, of, aided by eyes and
ears, 202; branchial skeleton
homologous with primate,
128; "gill slits" of embryo, 126

Ear (of man), external, chim-
panzee type of, Fig. 110, 213;
of foetal m., Fig. 109, 212

Ear (of man), middle, Fig. Ill,
216; auditory ossicles, Fig.
115, 221

Ear (of man), internal, Fig. 103,
203; labyrinth of, Fig. 104,
205, Fig. 105, 206

Ear muscles, reduced, 215

Eye (of man), owes develop-
ment to earliest primates, 90;
anthropoid and human, com-
pared, 195; of shark and man
compared, 192; horizontal
section of, Fig. 100, 193; iris
of, 199

Embryo (of man), Fig. 69, 127,
Fig. 108, 211;

Face (of man)

of Armenian, Fig. 89, facing

170
of Bushman, South Africa,

Fig. 89, facing 170
of Hottentot woman, Fig. 90,

facing 172
of pygmy, African, Fig. 89,

facing 170
of Roman athlete, frontispiece
of Nordic Swede, Fig. 90,

facing 172
of Tasmanian, frontispiece
of Tyrolese, Fig. 89, facing
170

Facial muscles, origin of the,
Fig. 23, 42

Facial nerve, the Fig. 24, 44

Foot derived from grasping
type, 55

Head, longitudinal section, Fig.
67, 124

Jaws (of man), primary jaws
completely masked by second-
ary, 106; traces of primary
upper j. in embryo, 106; can
be traced from earliest Am-
phibia to m., 107; Fig. 50, 80;
Fig. 53, 85; owes plan of
upper and lower j. to mam-
mal-like reptiles and earliest
mammals, 40; lower jaw of,
Fig. 37, 61; origin of zygo-
matic arch, 89; dominance of
superior maxilla in man, 89;
jaw muscles in, Fig. 61, 103;
muzzle of chimpanzee and
man compared, 142

Nose (of man), Jacobson's
organ lacking or vestigial in,
Fig. 65, 120; kinship of man
and anthropoids as shown by
external nose, 163; nasal
profiles, Fig. 88, 168; develop-
ment of, 162; of foetal man,
Fig. 84, 161; development of
nose in foetal man, 162;
olfactory pit in fcetal man,
Fig. 65, 120; Jacobson's organ
in fcetal man, Fig. 65, 120,
Fig. 82, 159

Palate (of man), comparative
Anatomy of the Human, Fig.

277

INDEX

Man — (Continued)

Palate (of man) — (Continued)
66, 121; palatal arch (of
white), Fig. 74, 140; develop-
ment of palatal region in
embryo, Fig. 65, 120; in em-
bryo, sixth week, Fig. 66, 121

Skull (of man), side view, Fig.
36, 59, Fig. 48, 78, Fig. 49, 79,
Fig. 50, 80, Fig. 51, 81; front
view, Fig. 44, 70; longi-
tudinal section, Fig. 83, 160;
top view (Cro-Magnon), Fig.
43, 69

Teeth (of man), origin of his
dentition, 90; difference be-
tween human and anthropoid,
141; traces of derivation of
teeth from Dryopithecus and
Sivapitkecus, 58; Dentition of,
Fig. 78, 148; "Dryopithecus
pattern" in teeth of, Fig. 80,
151; his teeth and his diet,
57; dental formula of an-
thropoids and man, 145;
development of, in embryo,
134, Fig. 71, 135; fovea
anterior and posterior, 149;
derived from anthropoids with
well-developed canines (Re-
mane), 142; front teeth of,
136; incisors of, 138; incisors,
central, of white boy, Fig. 72,
137; incisors, central, of an-
cient Egyptian, Fig. 72, 137;
incisors, three types of, Fig.
73, 139;incisors, upper central,
kinship of man and anthro-
poids as shown by, 139; milk
teeth of, Fig. 76, 146; milk
teeth of, as derived from
anthropoid type, 149; kinship
of human and anthropoid
lower molars, 146; compari-
son of molars with those of
cynodonts, 145; identity of
human and anthropoid molar
patterns, 69; molar, lower,
of Australian aborigine, Fig.
80, 151; molar, lower, of
white man, Fig. 80, 151;
history of upper and lower
premolars and molars, 146;
premolar, lower front, Fig.
75, 144

Cro-Magnon, highbred type of
skull of, 73; lower jaw,
sectioned, Fig. 45, 71; skull
of, side view, Fig. 42, 68;
skull of, top view, Fig. 43,
69

Ehringsdorf, see Man, Nean-
derthal (Ehringsdorf)

Heidelberg, chin of, 72; lower
jaw of, Fig. 37, 61, Fig. 45,
71; teeth of, 143; lower molar
of, Fig. 80, 151

Neanderthal, teeth of, 143

Neanderthal (La Chapelle-aux-
Saints), skull of, front view,
Fig. 44, 70; skull of, side
view, Fig. 42, 68; skull of,
top view, Fig. 43, 69

Neanderthal (Ehringsdorf), low-
er jaw of, Fig. 45, 71; central
incisors of, Fig. 72, 137;
lower front premolars of,
Fig. 75, 144; lower molar of,
Fig. 80, 151

Neanderthal (Krapina), "shovel-
shaped " incisors of, 138

Neanderthal (Le Moustier),
central incisors of, Fig. 72,
137; palatal arch of, Fig. 74,
140; dentition of, Fig. 78, 148;
characters of teeth of, Fig.
45, 71, 72

Piltdown, see Eoantkropus

Rhodesian, skull of, side view,
Fig. 42, 68; nose of, 72

Talgai, skull of, side view, Fig.
42, 68; prognathism of, 72

Trinil, see Pithecanthropus
Marmoset (Midas), skull of, Fig.

35, 58
Marsupials, relation to early mam-
mals of, 47, 51; Jacobson's
organ in, 159; nasal septum
in, 167; skull of, Fig. 53,
85
Mask, bony, of ganoids, 23; Fig.
11, facing 22; of earliest
Amphibia, 31; of reptiles, 43;
of mammal-like reptiles, 36;
of primitive living mammals,
43; starting-point of all
cranial bones, 28; covered by
facial and jaw muscles, 51
Mastiff, acromegaly and gigantism
in, 231

278

INDEX

Matthew, W. D., contributions to
palaeontology, 86; Eodelphis
named by, 47; evidence for
conclusions on ancestry of
placental mammals, 51

Maxillae, series of ten skulls show-
ing their evolution, Fig. 50, 80

Rhizodopsis

Palceogyrinus

Seymouria

Mycterosaurus

Scymnognathus

Ictidopsis

Didelphys

Notharctus

Chimpanzee, female

Man

covered with skin in early
Amphibia, and reptiles, 130;
unite with premaxillse in
anthropoids and man, 87;
origin of, in crossopts, 130
of Baphetes, Fig. 63, 108
of Eusthenopteron, Fig. 63, 108
of Seymouria, 32
Maxilla, inferior, development in
late mammal-like reptiles, 90;
ascending ramus forms mam-
malian joint with the squa-
mosal, 87
of chimpanzee, Fig. 45, 71
of Cro-Magnon man, Fig. 45, 71
of Dryopithecus, Fig. 45, 71
of Heidelberg man, Fig. 45, 71
of Neanderthal man (Ehrings-

dorf), Fig. 45, 71
of Neanderthal man (Le Mous-
tier), Fig. 45, 71
Maxilla, superior, homologous
in crossopts and early Am-
phibia, 107; evolution of, 87;
position of, 107; series show-
ing evolution of, Fig. 53,
85; dominance of, in man,
89; in achondroplasia, 230;
of cynodonts, secondary
palate derived from, 119; of
mammal-like reptiles, Fig.
50, 80; of mammals, Fig. 50,
80, 87
of Adapis, Fig. 53, 85
of Baphetes, Fig. 53, 85
of Captorhinus, Fig. 53, 85
of chimpanzee Fig. 53, 85

of Cynognalhus, Fig. 53, 85

of Eusthenopteron, Fig. 53, 85

of man, Fig. 53, 85

of Mycterosaurus, 34

of Scymnognathus, Fig. 53, 85

of Seymouria, Fig. 53, 85

of Thylacinus, Fig. 53, 85

McGregor, J. H., restorations of
primitive man by, 143

Meati, nasal, 161, 162

Meckel's cartilage, as primary
lower jaw, 102; articular bone
develops from, 112; of arma-
dillo, foetal, Fig. 114, 221;
of Devonian crossopts, 110;
of shark, Fig. 6, 13, Fig. 7,
17, Fig. 8, 18, 106

Median cartilage (of nose), origin
of, 167; growth of, in orang,
169

Megalichthys, lower jaw of, Fig.
64, 111

Meibomian glands, in human eye-
lid, 194

Melanesians, noses of, 169

Meniscus, of mammalian joint, in
Perameles, Fig. 22, 38, 39

Mental traits, human and anthro-
poid agree in basic, 74

Mesethmoid bone, origin of the,
167

Microchoerus, dentition of, Fig.
78, 148

Midas, top view of skull, Fig. 35,
58

Midgets, cause of, 231

Miller, G. S., on hind feet of
primates, 54

Mimetic muscles, origin of the,
43, 44

Miocene, Primates began to as-
sume human characters in,
64; anthropoid adaptations
during, 91

Molar teeth, identity of human
and anthropoid molar pat-
terns, 69; fovea anterior and
posterior in upper molars of
anthropoids and man, 149;
origin of, 90
of cynodonts, 116
of cynodonts and man com-
pared, 145
of fossil man, 143
of primitive man, 76

279

INDEX

Molars, lower, kinship of human
and anthropoid, 146
of chimpanzee, Fig. 79, 150
of Dryopithecus cautleyi, Fig. 79,

150
of D. fontani, Fig. 79, 150
of D. frickae, Fig. 41, facing 66,

Fig. 79, 150
"Dryopithecus pattern" in, 149,

Fig. 80, 151
of gorilla, Fig. 79, 150
of Homo heidelbergensis, Fig.

80, 151
of orang, Fig. 79, 150
Lower (left) m., of Dryopi-
thecus rhenanus, Fig. 38, 62
of Eoanthropus dawsoni, Fig. 38,

62, Fig. 41, facing 66
of Homo neanderthalensis (Le

Moustier), Fig. 38, 62
of Homo sapiens, Fig. 38, 62
of Leipsanolestes, Fig. 38, 62
of Parapithecus, Fig. 38, 62
of Pelycodus, Fig. 38, 62
of Propliopithecus, Fig. 38, 62
Molars, upper, of Dryopithecus
rhenanus, 149
of Homo neanderthalensis (Le

Moustier), Fig. 78, 148, 149
Upper (left), of Dryopithecus

rhenanus, Fig. 38, 62
of Homo neanderthalensis (Le

Moustier), Fig. 38, 62
of Homo sapiens, Fig. 38, 62
of Indrodon, Fig. 38, 62
of Pelycodus, Fig. 38, 62
of Propliopithecus (restored),
Fig. 38, 62
Mollusca, development of eye in
cephalopod, Fig. 95, 181;
paired eyes of higher, 178
Mongolia, Cretaceous mammals
from, 51; insectivores from
Cretaceous of, Fig. 29, 50
Mongolian face, the, 170
Mongolian nose, its shape, 164, 171
Mongolians, "shovel-shaped" in-
cisors of, 138
Monkeys, catarrhine, external ears
of, 214; face of, frontispiece,
56, Fig. 34, facing 56; incisors
of, 138; nasal chamber of,
161; nose of, 56, 57; orbital
axes of, Fig. 35, 58, 196;
skull of (Lasiopyga kolbi),

Fig. 36, 59; platyrrhine, as
offshoot from some primitive
tarsioid stock, 56; face of
(Cebus capucinus), Fig. 34,
facing 56; lips of, 56; nose of,
56; orbital axes of Midas,
Fig. 35, 58, 196
Morton, D. J., on hind feet of

primates, 54
Montana, mammalian teeth from
Basal Eocene of, 53; Eodelphis
from Upper Cretaceous of, 47
Mouth, as dominant element of
face, 4; conclusions from
history of, 152; origin of,
uncertain below ostracoderms,
101; nasal sac as outgrowth
of, 154

of ancestral prevertebrate
forms, 94

of Amphioxus, Fig. 54, 92, 129

of annelid worms, 6

of Cephalaspis (restoration),
Fig. 57, 95

of crossopts, 130

of jellyfish (Tessera), 4, Fig. 1, 5

of Kiaeraspis (restoration), Fig.
57, 95

of lamprey, adult, 129

of lamprey, larval, 129

of man, foetal, third week, Fig.
69, 127

of ostracoderms, 129

of Paramecium, Fig. 1, 5

of platypus, 131

of shark, Fig. 5, facing 12
Mouth-legs, of Orchestia, Fig. 2,
facing 6

of trilobites, 6
Mouth pouches, embryonic, 94

of larval lamprey, longitudinal
section, Fig. 56, 94

of rabbit, embryo, Fig. 56, 94

of sharks and embryo verte-
brates, supported by cart-
ilaginous bars, 102
Muscles

of accommodation (ciliary), 193

of accommodation, in eyes of
Sepia, 180

of check and lips, important to
new-born mammals, 134; con-
strictor, of gill arches: jaw
muscles of shark derived
from, 104

280

INDEX

Muscles — (Continued)
of the ear, 133

of the ear, reduced in man, 215
of the eyeball, in man, Fig. 98,

190
of vertebrate eye, 191
of the eye of shark (Chlamy-

doselachus), Fig. 6, 13, 15
Facial, origin and development
of the, 43; origin of, in mam-
mals, 132
of gorilla, Fig. 23, 42, 67, 124
of man, Fig. 23, 42
geniohyoglossus, of anthropoids,

126
of man, Fig. 67, 124, Fig. 68, 125
of monkey, Fig. 68, 125
of jaw development associated
with change of jaw form, 116;
evolution of the, Fig. 61,
103
of fishes, 104

of shark, their derivation, 104
of chimpanzee, Fig. 61, 103
of Chlamydoselachus, Fig. 8, 18,

also Fig. 61, 103
of Cynognathus, Fig. 61, 103
of Didelphys, Fig. 61, 103, also

49
of Eryops, Fig. 61, 103
of man, Fig. 61, 103
of Notharctus, Fig. 61, 103
of Polypterus, Fig. 61, 103
of Scymnognathus, Fig. 61, 103
masseter, 116; at corner of
mouth of some reptiles, 131;
orbicularis oris, 133; orbi-
cularis oris of catarrhine
monkeys, 56; platysma, the
origin of the, 43; pterygoid,
116-117; pterygoid, external,
and mammalian joint, Fig.
22, 38, 39; sphincter colli,
43, 132
of Echidna, Fig. 23, 42
of Sphenodon, Fig. 23, 42
temporal, 116

of tongue (geniohyoglossus) in
anthropoids, Fig. 67, 124
Muscle fibres, striped, function of

the, 19
Mycterosaurus (Permo-Carbon-
iferous), dentition of, Fig. 77,
147; skull of, Fig. 19, 33,
Fig. 48, 78

Nares, of crossopts, 24

Naris, internal, series of skulls
showing evolution of, Fig.
53, 85
of Adapis
of Baphetes
of Captorhinus
of chimpanzee
of Cynognathus
of Eusthenopteron
of man (Australian aboriginal)
of Scymnognathus
of Seymouria
of Thylacinus

Nasal bones, series of skulls show-
ing evolution of, Fig. 49, 79;
their origin in Amphibia
30; retained from fish to
mammals, 86; in advanced
lemuroids, 60

Nasal chamber, median partition
of, 158; sinuses and antra of,
162; of mammal-like reptiles,
158; of man and monkeys,
compared, 161

Nasal field, in embryonic develop-
ment, 166

Nasal meati, 161; connections of
sinuses with, Fig. 85, 163

Nasal pit of larval lamprey, Fig.
56, 94

Nasal sac, embryonic origin of,
154; of embryo sharks and
mammals, 154

Nasal septum, rates of develop-
ment of the, 167

Naso-buccal groove, of sharks,
Fig. 66, 121, 122, 154,
157

Naso-lacrymal duct, in man,
194

Naso-pharyngeal passage, 119

Nautilus, eye of, 181

Neanderthal man, see Man,
Neanderthal

Negritos, the nose of, 169

Negro, the iris of, 199; develop-
ment of the nose in, 167; the
nose of, 169; Fig. 88, 168;
the nose of, infant, Fig. 88,
168

Negro pygmy, nose of the, 164

Nematodes, effect of ultraviolet
rays on, 174

Neoceratodus, 25

281

INDEX

Nerve, seventh cranial activates
sphincter colli, 43; facial,
chief branches of, in man
and gorilla, Fig. 24, 44; facial,
of Sphenodon, Fig. 23, 42;
oculomotor, of chimpanzee,
198; olfactory, course and
function of, 155; optic, de-
scription of, 187, 188; optic,
human, function of, 191;
optic, of Sepia, 180; of
semicircular canals, 204, 206

Nerve cells, olfactory, 157

Nervous system of primates,
studies of, 63

New Mexico, Notharctidse from
Eocene of, 54; early placental
mammals from, 52

Nictitating membrane, vestiges
of, in man, 194

Norway, ostracoderms of, 10

Nose, progressive stages in devel-
opment of, vertebrate, 157;
shapes of the human, 164,
Fig. 89, facing 170; great
diversity of form in the, 172;
extreme forms of, Fig. 89,
facing 170; factors controlling
form of the, 168-171; effect
of the bony palate on, 169;
effect of premaxillse on, 168;
hereditary factors in 172, 236;
development of human, 162;
development in foetal and
adult man, 163; varying rates
of development of its parts,
167; Prof. Schultz' studies
on growth of, 172; embryonic
stages of human, Fig. 65, 120,
Fig. 82, 159; human, as index
of character, 220; shows kin-
ship of man and anthropoids,
163; nasal sinuses of man and
anthropoids, 161; septal car-
tilage of human, Fig. 88, 168;
origin of median cartilage in
mammalian, 167; olfactory
capsules of mammal-like rep-
tiles, 158; naso-buccal groove
of shark, Fig. 66, 121, 154,
157; nasal meati, 161; nasal
sac, embryonic origin in
shark and mammal, 154;
embryonic development of
mammalian, 166; Jacobson's

organ, 158; lateral (or alar)
cartilage, 167; primary func-
tion of the, 154; essential
parts of the, 155; bridge of
the, 170; the humped n.,
cause of, 169; the Mongolian
nose, 171; the pug nose,
cause of, 169, 171; the wide
nose, cause of, 169; shape of,
in achondroplasia, 169, 230

in acromegaly, 171

in cretinism, 171

of gorilla, 170

of gorilla, foetal, Fig. 84, 161

of catarrhine monkey, 56

of shark, 154

of man, foetal, Fig. 84, 161

of man, infant, 167

of Armenian, Fig. 89, facing
170

of Australian aboriginal, 169

of South African Bushman, Fig.
89, facing 170

of Hittite type, 169; Fig. 89, fac-
ing 170

of Melanesian, 169

of Mongolian, 164

of negrito, 169

of negro, 169, Fig. 88, 168

of negro child, Fig. 88, 168

of Papuan, 169

of African pygmy, 164, Fig.
89, facing 170

of Rhodesian man, 72

of Tasmanian, 169

of Tyrolese, Fig. 89, facing 170

of white adult, Fig. 88, 168

of white child, Fig. 88, 168
Nostrils

of catarrhine monkeys, 57
Nostrils, internal (choanse)

of early amphibia, Fig. 53, 85,
118

of lung fishes, 157
Notharctidse, from Eocene of
Wyoming and New Mexico,
54; compared with lemurs of
Madagascar, 54
Notharctus (Eocene), compared
with chimpanzee and man,
65; position of eyes in, Fig.
35, 58, 196; jaw muscles of.
Fig. 61, 103; olfactory cham-
ber of, 196; skeleton of N.
osborni, Fig. 32 facing 54;

282

INDEX

Notharctus (Eocene) — {Continued)
skull of, side view, Fig. 33, 55,
Fig. 36, 59, Fig. 48, 78; skull
of, top view, Fig. 35, 58

Notochord, 21

Nycticebus, external ear of, Fig.
110, 213

Ocellus

of flatworm (Planaria), Fig. 2,

facing 6
of jellyfish (Catablema), Fig. 91,

175
of jellyfish (Sarsia), Fig. 91, 175
of sand flea (Orchestia), Fig.
2, facing 6
Octopus, eyes of, 179
Oculomotor nerves, of chimpan-
zee, 198
Olfactory capsule, its place in the
skull structure, 83; in em-
bryonic development, 167;
the value of double, 156;
in human embryo, 162, Fig.
65, 120
of mammal-like reptiles, 158
of shark, Fig. 6, 13, 14, Fig. 7,
17, 122, 154, Fig. 81, 155
Olfactory chamber

of early amphibia, 118
of Lemur, 58
of Notharctus, 196
of Notharctus osborni, 56
Olfactory membrane, function of

the, 158
Olfactory nerve, course and func-
tion of the, 155
Olfactory nerve cells, as special-
ized cell of skin, 157
Olfactory pit,

in human embryo, Fig. 65, 120
of shark, 122
Olfactory sac, 157
Olfactory sense organs, 155
Oligocene, lower, separation of
man from early anthropoids
in (Osborn), 74
Ontogenetic study of physiog-
nomy, 224
Opercular notch, eardrum formed

in location of, 89
Opercular tract, elimination of
plates of, in early amphibia,
Fig. 17, 30, 114
Opossum, fossil (Eodelphis), 47;

skull of, Fig. 48, 78; compared

to that of Didelphys, Fig. 27,

Opossum, recent (Didelphys), most

primitive marsupial of today,

47; with young, Fig. 26,

facing 46; jaw muscles of,

Fig. 61, 103; skull compared

with that of Eodelphis, Fig.

27, 48; skull of, Fig. 28, 49

Optic capsule, of shark, Fig. 7, 17

Optic cups, formation of the, Fig.

97, 185, 187; development of

retina from, in vertebrates,

181

Optic nerve, description of the,

188; function of the, 191; of

Sepia, 180

Optic pouch, of the jellyfish, 175

Oral cartilage, of shark and

embryo vertebrates, 102
Orang, pattern of papillae vallatae
similar to that in man, 123;
external ear of, Fig. 110, 213,
214; palatal arch of female,
Fig. 74, 140; lacrymal bone
of, 200; nose of, 169; skull of
young, front view, Fig. 102,
197; teeth, lower molar, Fig.
79, 150; tongue of, 123
"Orang type," of human ear,
Fig. 110, 213
Orbicularis oris muscle

of anthropoid apes and man,

133
of catarrhine monkeys, 56
Orbital axes

of lemuroids, Fig. 35, 58, 196
of platyrrhine monkeys, Fig. 35,

58, 196
of catarrhine monkeys, Fig. 35,

58, 196
of anthropoids, Fig. 35, 58, 196
Orbits

of advanced lemuroids, 60
of lower primates, 60
of orang, 169

of Tarsius, Fig. 31, facing 53, 60
Orchestia (Sand-flea), Fig. 2, fac-
ing 6
Organ of Corti, the, Fig. 103,

203, 204
Organs, lateral line, of fishes, 206
Organ, parapineal, 186; pineal, 186
Ornithorhynchus, mouth of, 131

283

INDEX

Oronasal groove, see nasobuccal
groove

Osborn, H. F., evidence for his
conclusions on ancestry of
placental mammals, 51; view
of separation of man and
apes from primitive stock, 74

Ossicles, auditory, see Ear, audi-
tory ossicles

Osteolepidae (Cross opterygii)
closely related to Amphibia
of Carboniferous, 114

Osteolepis (Devonian), skull of,
cross section, Fig. 9, facing 20;
seen from above, Fig. 11, fac-
ing 22; spiracular cleft in, 209

Ostracoderms, probably ancestral
to cyclostomes, 186; a modern
descendant of the, Fig. 59, 97;
their use of cilia for ingestion,
95; ingestion transitional be-
tween ciliary and predacious,
97; origin of mouth jaws and
teeth uncertain below, 101;
mouth of, 129; denticles in
skin of, 117; teeth of
(Lanarkia), 117; Prof. Patten
on, 8; Stensio on cephalaspid
o., 94; Anaspida, characters
of the order, 96; Fig. 4, 11
Cephalaspis, restoration of, Fig.
4, 11; restoration of head of,
Fig. 57, 95
Kiaeraspis, restoration of head

of, Fig. 57, 95
Lanarkia, shagreen denticles of,

100
Pteraspis, restoration of, Fig. 4,

11
Pterolepis nitidus, restoration
of, Fig. 4, 11, also Fig. 58, 96

Otic capsule, as a component of
the chondrocranium, 83; of
shark, Fig. 7, 17, Fig. 81, 155

Otic notch, in early amphibians,
29, 209, Fig. 17, 30
of Seymouria, 32, Fig. 19, 33
in reptiles, 209
Otoliths, 206

Palaogyrinus, skull of, showing
loss of opercular series, Fig.
17, 30; side view of, Figs.
48-52, 78-82

Palatal arches, reduction in size

of teeth, factor in shortening
of, 143
of gibbon, female, Fig. 74, 140
of gorilla, male, Fig. 74, 140
of chimpanzee, female, Fig. 74,

140
of orang, female, Fig. 74, 140
of Neanderthal man (Le Mous-

tier), Fig. 74, 140
of modern white man, Fig. 74,
140
Palatal bone, 83
Palatal region

of cynodonts, Fig. 52, 82

of Scymnognathus, Fig. 53,85, 118

progressive changes in, Fig. 53,

85, 118
of mammals, Fig. 53, 85, 119
in human embryo, 120
Palate, bony, its effect on shape
of nose, 169; comparative
anatomy of human, Fig. 66,
121; cleft, human, 228; cleft
palate, in Felis leo, Fig. 66,
121; fleshy, possible rudi-
ments in Scymnognathus, 119;
of lizard, Fig. 66, 121;
primitive, formation of, 122;
reptilian, 122; secondary, in
human embryo, Fig. 66, 162;
of cynodonts, Fig. 52, 119;
soft, of mammals, 119
Palatine bone, of cynodonts, 119
Palatoquadrate,

of Devonian crossopts, 109
of Diadectes, Fig. 62, 105
of shark, Fig. 6, 13, 17, Fig. 7,
17, Fig. 8, 18, 106
Palatoquadrate cartilages, 102
Paleocene of New Mexico, early

placental mammals in, 52
Pantotherian, dentition of, Fig.

77, 147
Papillae vallatse, of orang similar

to those of man, 123
Papuans, noses of, 169
Paramacium (Slipper animalcule),
face of, 4; mouth of, Fig. 1, 5
Parapineal eye, Fig. 97, 185; as

directional organ, 200
Parapineal organ, origin of, 187;

in pre-chordates, 186
Parapithecus, lower jaw of P.
fraasi, Fig. 37, 61; left lower
molar of, Fig. 38, 62

284

INDEX

Parasphenoid, of fish, 22; enlarge-
ment in amphibians of, 31

Parietal bones, evolution of, Fig.
49, 79; of opossum, 49; as
components of dermocranium,
83; among dominant elements
of human skull, 87

Parker, G. II., cited on hearing of
fishes, 206

Parker, W. K., cited on embry-
ology of sturgeon, 209

Patten, William, theory of deriva-
tion of vertebrates, 7, 8, 92,
182; cited on derivation of
vertebrate eye, 182

Pecten, eyes of, 178

Pelvic floor, Sir Arthur Keith on
the primate, 63

Pelvis, evolution of primate, 63

Pelycodus, lower jaw of, Fig. 37,
61; left lower and upper
molars of, Fig. 38, 62

Pen-tailed tree-shrew, Fig. 30,
facing 52

Perameles, formation of meniscus
in embryo of, Fig. 22, 38, 39

Periotic mass, fusion of squamosal
bone with, in mammals, 88

Permian period, labyrinthodonts
and stegocephalians of the,
115; Mycterosaurus, of the,
34; Seymouria, of the, 32

Permocynodon, middle ear of, Fig.
112, 217

Pharynx, function in respiration
of, 162
of Amphioxus, 98
of larval lamprey, 98

Philtrum, of the lip, in man, 133;
embryonic development of
the, 166

Phototropism, 174

Physiognomy, anthropological
method of study of, 224;
Aristotle on, 220; the author
analyzes his own face, 225-
229; clinical method of study
of, 224; Darwin's study of,
223; Duchenne's study of
(experimental method), 223;
embryological study of, 224;
evolutionary method of study
of, 223; experimental method
of study of (Duchenne's),
223; genetic method of study

of, 224; origins of modern
science of, 222; physiological
method of study of, 224;
psychiatrist's method of study
of, 225; psychoanalyst's
method of study of, 225;
psychologic method of study
of, 224; Sir Charles Bell's
study of, 222; study of cor-
relation between crime and
types of, 225

Piltdown man (Eoanthropus),
canine tooth of, 141; char-
acters of, 72, 73; lower jaw of,
Fig. 37, 61; Fig. 45, 71, 143;
lower molar of, Fig. 38, 62;
Fig. 41, facing 66

Pineal eye, Fig. 97, 185, 200

Pineal organ, origin of, 187; in
pre-chordates, 186

Pithecanthropus (Trinil man),
characters of, 72, 73; skull
of (side view), Fig. 42, 68;
skull of (top view), Fig. 43, 69

Pituitary glands, effects of
diseased, 171

Placental mammals, their fore-
runners from Mongolia, 51;
in Basal Eocene and Pale-
ocene of New Mexico, 52

Planaria, eyes of, as directional
organs, Fig. 93, 178; head and
tail differentiation of, Fig. 2,
facing 6; location of eyes of,
Fig. 92, 177

Plant life, origin in Archeozoic
era, 27

Plate, L., cited on origin and
development of the eye, 174-
188; summary of literature
on eyes of invertebrates and
vertebrates, 174; on eyes of
Amphioxus, 183, 184; on eye
capsules of flatworm, Fig. 93,
178; on human vision, foot-
note, 174; on paired eyes of
vertebrates, 178

Platypus, believed related to
some mammals of Age of
Reptiles, 47; mouth of, 131

Platyrrhine monkeys, see Monkeys,
platyrrhine

Platysma muscle, origin of, 43

Pleistocene, lower, already several
types of man in, 73

285

INDEX

Plica semilunaris, of human eye,
Fig. 101, 194; as vestige of
third eyelid, 194

Pliocene, fossil human record a
blank during the, 70, 142;
reduction of human canine
teeth may have occurred dur-
ing the, 142

Polyplocodus, teeth of, Fig. 18,
following, 30

Polypterus, embryo of, Fig. 14, 26;
jaw muscles of, Fig. 61, 103;
representative of lobe-finned
ganoids, 24

Postfrontal bone, eliminated by
time of earliest mammals, 88,
90

Postorbital bone, joint process of
frontal and malar replace, 90;
eliminated by time of earliest
mammals, 88, 90; evolution
of, Fig. 51, 81

Postsplenial bone, series of skulls
showing evolution of, Fig.
52, 82; reduction of, 88; of
Megalichthys, Fig. 64, 111;
of Trimerorhachis, Fig. 64,
111

Posture, its effect upon develop-
ment of face, Fig. 36, 59,
64, 66; characters of early
primates adapted to, 67,
68

Prearticular bone, of Trimeror-
hachis, Fig. 64, 111

Pre-chordates, eyes of, 186

Predaceous habits, organization
of primitive vertebrates
adapted to, 101

Prefrontal bone, evolution of,
Fig. 51, 81; eliminated by
time of earliest mammals,
88

Premaxilla, evolution of, Fig. 50,
80; Fig. 53, 85; position of,
107; effect on shape of nose,
168; unites with maxilla in
anthropoids and man, 87; of
crossopt and early amphibian
are homologous, 107; of
Baphetes, Fig. 63, 108; of
Eusthenopteron, Fig. 63, 108;
covered with skin in early
amphibians and reptiles, 130;
origin of, in crpssoptSj, 130

Premolars, in primitive man, 76;
origin of, 90; of cynodonts,
116; of fossil man, 143; of
Dryopithecus, Sivapithecus,
Neanderthal and Homo
sapiens, Fig. 75, 144; front
lower, of anthropoids, 144;
nearest affinities of human,
144
Preoperculum, elimination of, Fig.

17, 30, 114
Presphenoid bone, 167
Pre- vertebrates, see Chordates
Prevomer bones, evolution of,
Fig. 53, 85; of Devonian
crossopts, 100
Primates, mammals of Basal
Eocene of Montana approach
the, 53; family Notharctidse,
54; hind foot of, always of
tree-grasping type, 54; com-
parison of hands and feet of
fossil and recent, 54; arboreal
stage passed through by all,
54; skeleton of primitive fossil,
Fig. 32, facing 54; skull of
primitive fossil, Fig. 33, 55;
faces of lower, Fig. 34, facing
56; traces of insectivorous
dentition in, 57; ears of the
lower, 57; top view of skulls
of, Fig. 35, 58; side view of
skulls of, Fig. 36, 59; Epitome
of Fossil History of, Figs. 37,
38, 61, 62; value of study of
fossil and recent, 60; rare as
fossils, 60; relation of upper
jaws to eyes in, 60; Keith
cited on diaphragm, abdomen
and pelvic floor of, 63; pro-
gressive series presented by
brains of, 63; agreement of
results of studies on internal
and external anatomy and
fossil history of, 63; time of
assumption of human char-
acters of, 64; enlargement of
brain characteristic of, 64;
correlated use of eyes, hands
and feet in, 64; man derived
from Old World, 65; develop-
ment of eyes of, 65; char-
acters adapted to diet and
posture in, 67; characters of
man, and 67; man owes

286

INDEX

Primates — (Continued)

development of eyes to early,
90; postorbital bar replaced
by process from frontal and
malar bones in earliest, 90;
character of tongue in, 123;
branchial skeleton of, homo-
logous with human, 128;
salivary glands of, 129; lips
of, 133; Jacobson's organ
lacking or vestigial in higher,
159; nasal septum of, 167;
eyes of primitive, 196; re-
duced olfactory apparatus in
higher, 196

"Primitive streak," mouth of
Tessera represents, 5

Pro-anthropoids, man derived
from, 69; changes of skull in
arboreal, 91

Protista, supposed rudimentary
eyes of, 174

Protozoa, among earliest marine
invertebrates, 8

Psychiatrist, method of study of
physiognomy by, 225

Psychoanalyst, method of study of
physiognomy by, 225

Psychologic method of study of
physiognomy, 224

Pteraspis, Fig. 4, 11; mouth of, 96

Pterolepis nitidus, Fig. 58, 96

Pterygoid bone, of Diadectes, Fig.
62, 105; effect of increase in
size of, 117

Pterygoid muscle, origin of men-
iscus in, Fig. 22, 38; Gaupp
cited on, 39; influence of its
development on skull, 117

Pulp cavity, in formation of teeth,
134, Fig. 71, 135

Purple, visual (rhodopsin), 189

Pygmy, African, nose of the, 164,
Fig. 89, facing 170

Quadrate bone, 39; evolution of,

Fig. 53, 85; of Diadectes, Fig.

62, 105
Quadratojugal bone, evolution of,

Fig. 52, 82; Fig. 53, 85;

reduction of, 88

Rabbit, embryo, mouth pouch of,
Fig. 56, 94; labyrinth of, Fig.
104, 205

Radial symmetry, gives way to
bilateral, 6

Remane, A., cited on incisors of
chimpanzee, 138, 141; study
of anthropoid teeth by, 142;
cited on front lower pre-
molar of man and anthro-
poids, 145

Reptiles, Seymouria most primi-
tive, 32; sphincter colli of,
43; period of dominance of,
45, Fig. 25, 46; loss of inter-
and supra-temporals from
skull of early, 89; progressive
changes in teeth of, Fig. 53,
85, 115; naso-buccal channel
of, 122; skin-covered maxillae,
premaxillse and dentary of
early, 130; muscle at corner
of mouth of some recent, 131;
Jacobson's organ in, 158;
stage in development of nose
of human embryo like that of,
162; tympanum of, 217; mam-
mal-like, skulls of earlier and
later, Fig. 20, 35; progressive
upgrowth of dentary bone of,
Fig. 21, 37, 108; initial stages
in formation of hair possibly
developed in Triassic, 42;
opossum similar to Triassic,
48, Fig. 28, 49; superior
maxillary of, Fig. 50, 80, 87;
inferior maxillary in, 87;
origin of temporal fossa and
zygomatic arch in early, 89;
development of temporal fossa
in later, 90; palatal region of,
Fig. 53, 85, 118; nasal septum
of, 167; relation of parts of
middle ear in, Fig. 112, 217;
internal ear of advanced, 218;
angular bone of, 218

Reptilian postorbital bar, loss of,
by early mammals, 90

Reptilian stage, in development of
auditory ossicles, Fig. 115,221

Respiration, origin and function
of the diaphragm, 41; of
early amphibians, 118; of
mammals, 119; of sharks,
Keith cited on, 122; of
dipnoan fishes, Keith cited
on, 122; of air-breathing
fishes and amphibia, 157

287

INDEX

Retina, of the squid (Sepia), 180;
of cephalopods, 181, Fig. 95,
181; of vertebrates, developed
from optic cup, 181; forma-
tion of the, Fig. 97, 185; of
dorsal eyes in pre-chordates,
Studnicka cited on, 186, 187;
apparently represents in-
verted patch of epithelium,
187; layers of the, 188;
likened to sensitive plate of
camera, 189; function of
human, 191; of shark, Fig.
99, 192; human, Fig. 100, 193

Rhinarium, of lemur, 56

Rhizodopsis, skull of, Fig. 17, 30;
Figs. 48-52, 78-82

Rhodesian man, skull of, Fig. 42,
68, 72

Rhodopsin (visual purple), 189

Ribs, their origin, 21

"Rods," of the primitive eye, 175;
in eyes of cephalopods, Fig.
94, 179, 180; in eyes of
vertebrates, 180; in organ of
Corti, 204

Rods and cones, as layer of retina,
188; of human eye, 190

Rotifers, effect of ultraviolet rays
on, 174

Ruge, G., on origin of facial
muscles, 44; researches of,
show anatomy of facial
muscles most like in man and
anthropoids, 132, 133; mono-
graph on facial musculature
of, shows likeness between
ear muscles of chimpanzee
and human embryos and
children, 215

Sacculus, of inner ear of lower
vertebrates, Fig. 104, 205-206

St. Bernard dog, acromegaly and
gigantism in, 231

Salamander, skull of foetal, Fig.
62, 105; embryo of, Fig. 14,
26

Salivary glands, of man and apes,
129

Sand-flea (Orchestia), Fig. 2, fac-
ing, 6

Sarsia, eye of, Fig. 91, 175

Scales, origin of, in skin of pre-
vertebrates, 101; of crossopts,

same nature as covering of
primary jaws, 106

Scallop (Pecten), eyes of, 178

Schultz, A. H., cited on hind feet
of primates, 54; on nose of
human foetus, 164; on devel-
opment of human nose, 167;
studies on human nose, 172

Sclera, of shark, Fig. 99, 192; of
human eye, Fig. 100, 193

Sclerotic layer, of eye of verte-
brates, 188

Scylacosaurus, dentition of, Fig.
77, 147

Scymnognathus, skull of, Fig. 20,
35; Fig. 21, 37; Figs. 48-53,
78-85; jaw muscles of, Fig.
61, 103

Sea-cucumber, larva of (Auri-
cularia), Fig. 55, 93

Sebaceous glands, origin and
function of, 41

Semicircular canals, of ear of
shark, 16; of human ear,
202, Fig. 103, 203; of primi-
tive fish, 204; nerves of the,
204, 206; of frog, Fig. 106,
208

Sense organs, origin from skin of,
101; mystery of their origiD,
156; value of bilateral ar-
rangement of, 156

Sepia (squid), structure of eyes
of, Fig. 94, 179, 180

Septal cartilage, in man, Fig. 88,
168

Septum, nasal, origin of, 167;
rates of development of, in
anthropoid and man, 167

Seymouria, restoration of face of,
frontispiece; most primitive
reptile, 32; otic notch of, 32;
skull of, Fig. 19, 33; Figs.
48-53, 78-85; teeth of, 118

Shagreen, of skin, origin of teeth,
19; in primitive sharks, 109

Shagreen denticles, development
of, into teeth, Fig. 60, 99;
skin of pre-vertebrates gave
rise to, 101

Shark, Devonian (Cladoselache),
restoration of face of, frontis-
piece; our own face shown in
that of, 12; recent (Chlamy-
doselachus), face of, Fig. 5,

288

INDEX

Shark, Devonian — {Continued)
facing 12; instruments of pre-
cision in head of, Fig. 6, 13,
14; olfactory capsules of, Fig.
6, 18, 14; Fig. 7, 17, Fig. 81,
155; eye muscles of, Fig. 6,
13, 15; shark nearer to man
than to invertebrates, 14,
102; and his prey, 15; taste
organs of, 16; "ampullae" in
head of, 16, 204; "internal
ears" of, 16; cartilaginous
skeleton of head of, Fig. 7,
17; primary jaws of, Figs. 7,
8, 17, 18, Fig. 62, 105;
palatoquadrate of, Figs, 7,
8, 17, 18; labial cartilages of,
Figs. 7, 8, 17, 18; hyoid of,
Fig. 7, 17; hyomandibula of,
Figs. 7, 8, 17, 18; jaw
muscles of, Fig. 8, 18, Fig.
61, 103; derivation of jaw
muscles of, 104; otic capsule
of, Fig. 7, 17, Fig._ 81, 155;
optic capsule of, Fig. 7, 17;
skin of the, 19; chemical
composition of skeleton of,
23; facial expression of, 19;
mouth pouches of embryonic,
94; three stages in develop-
ment of teeth of, Fig.^0, 99;
visceral arches in predecessors
of, 104; mouth pouches sup-
ported by cartilaginous bars,
104; secondary jaws repre-
sented only by skin, 106;
development of teeth in typ-
ical, 109; less advanced than
crossopt, 113; tongue of, 123;
dissection of head of, Fig.
81, 155; oronasal groove of,
Fig. 66, 121, 154, 157; method
of respiration of, 122; mouth
of, 130; spiracle of, Fig. 81,
155; eye of, nearer to that of
man than to any invertebrate
eye, 191; horizontal section of
eye of, Fig. 99, 192; laby-
rinth of, Fig. 104, 205

Shark-like stage, of human eye,
191

Shoulder-girdle, Watson cited on,
of fossil amphibians, 28, Fig.
15, 28

Shrew, see Tree-shrew

Shylock, and the shark, 12

Silurian and Devonian ostraco-
derms, 10, Fig. 4, 11; Kiser
and Stensio cited on, 10, 11,
12, 94, 97, 98; Lanarkia, 100

"Simian shelf" of Piltdown man,
Fig. 45, 71, 143

Sinus, nasal, of man and anthro-
poids, 161, 162; frontal, con-
nection with nasal meati,
Fig. 85, 163; ethmoid, con-
nection with nasal meati,
Fig. 85, 163; sphenoid, con-
nection with nasal meati,
Fig. 85, 163

Sivapithecus, traces of derivation
of human dentition from,
58; lower jaw of, Fig. 37, 61;
dental formula of, Fig. 37,
61; front lower premolars of,
144, Fig. 75, 144; upper
molars of, 140

Skeleton, of shark, its chemical
composition, 23; of Noth-
arctus, Fig. 32, facing 54

Skin, of shark, 19; potentialities
of, 100; structures derivative
from, 101; origin of some
sense organs in, 101; origin
of teeth in, 101, 109; dentary,
maxillae and premaxillag of
advanced crossopts covered
by, 130; on bill of Platypus,
131

Skull, heritage of the, 20, 28, 89;
structure of the, 21, 83;
comparison of lobe-finned
ganoid, with early amphibian,
29, 107; simplification of the,
31; formation of mammalian
joint of, 39, 90; of some
placental mammals ap-
proaches that of lowest Pri-
mates, 53; dominant elements
of human, 87; evolution of
human, from fish to man,
Figs. 48-53, 78-85; changes
in lateral view of, from fish
to man, 86-91; factors deter-
mining changes in structure
of, 88-89; genesis of temporal
bone of, 88; loss of bones cov-
ering branchial chamber of,
89; changes of, in arboreal
pro-anthropoids, 91; attach-

289

INDEX

Skull — (Continued)

ment of primary upper jaw
to, 104, Fig. 62, 105; dentary-
squamosal contact in, 108,
109; Keith cited on develop-
ment of, 122; position of
temporal region of, condi-
tioned by size of brain, 170;

of achondroplastic dwarf, 230

of Adapts, Fig. 53, 85

of Arctocebus, top view, Fig. 35,
58

of Australopithecus, Fig. 42, 68,
72; side view, Fig. 46, facing
72

of Baphetes, under side, Fig. 53,
85, Fig. 63, 108

of chimpanzee,

top view, Fig. 35, 58, Fig.

43, 69
side view, Fig. 36, 59
near to human, 65
front view, Fig. 44, 70
bones of, Figs. 48-53, 78-85
longitudinal section, Fig. 83,

160
young, front view, Fig. 102,
197

of Cro-Magnon, side view, Fig.
42, 68; top view, Fig. 43, 69;
high-bred, 73

of Cynognathus, Fig. 53, 85

of Deltatheridium, Fig. 29, 50

of Diadectes, Fig. 62, 105

of Eodelphis, Fig. 27, 48, Fig.
48, 78

of Eusthenopteron, Fig. 53, 85,
Fig. 63, 108

of gorilla, young, Fig. 102, 197

of Hylobates (gibbon), Fig. 35,
58

of Ictidopsis, Fig. 20, 35, Fig. 21,
37, Fig. 28, 49, Figs. 48-52,
78-82

of Lasiopyga, side view, Fig.
36, 59

of Loxomma allmani, Fig. 16,
facing 28

of man, Australian aboriginal,
Fig. 53, 85; bones of, Figs.
48-52, 78-82; side view, Fig.
36, 59; longitudinal section,
Fig. 83, 160; infant, front
view, Fig. 102, 197; Modern
European, Fig. 44, 70

of Midas (marmoset), Fig. 35,

58
of Mycterosaurus, Fig. 19, 33;

bones of, Figs. 48-52, 78-85
of Neanderthal (Chapelle aux

Saints), side view, Fig. 42, 68;

top view, Fig. 43, 69; front

view, Fig. 44, 70
of Notharcfus osborni, side view,

Fig, 33, 55, Fig. 36, 59; top

view, Fig. 35, 58; bones of,

Figs. 48-52, 78-82
of opossum, recent, Fig. 27, 48,

Figs. 49-52, 79-82
of orang, young, Fig. 102, 197
of Osteolepis, cross-section, Fig.

9, facing 20; top view, Fig.

11, facing 22
of Palwogyrinus, Fig. 17, 30;

bones of, Figs. 48-52, 78-82
of Piltdown, Fig. 42, 68, 141
of Pithecanthropus, side view,

Fig. 42, 68; top view, Fig. 43,

69; ape-like features of, 72
of Primates, showing progres-
sive shortening of the muzzle,

Fig. 36, 59
of Rhizodopsis, Fig. 17, 30;

bones of, Figs. 48-52, 78-82
of Rhodesian man, Fig. 42, 68;

gorilla-like details of nose, 72
of salamander (fcetal), Fig. 62,

105
of Scymnognathus, Fig. 20, 35;

posterior view, Fig. 21, 37;

bones of, Figs. 48-53, 78-85
of Seymouria, Fig. 19, 33; bones

of, Figs. 48-53, 78-85
of Talgai man, Fig. 42, 68;

proto-Australoid type of, 72;

muzzle of, 143
of Tarsius spectrum, Fig. 35, 58
of Thylacinus, posterior view,

Fig. 21, 37; under side of, Fig.

53, 85
of Zalambdalestes lechei, Fig. 29,

50
Slipper animalcule, mouth of, 4,

Fig. 1, 5
Smelling organs, of shark, 14, 15,

17, Fig. 81, 155, 154-156
Smell, sense of, not dominant in

anthropoid apes, 65; sight

developed at expense of, by

pro-anthropoids, 91

290

INDEX

Smith, G. Elliot, cited on evolution
of primate brain, 63

Sonntag, Charles F., work on
facial muscles, 132

Spaniel, King Charles, ateleosis
in, 231

Spectral tarsier (Tarsius), Fig. 31,
facing 53

Spinal cord, of Ampkioxus (sec-
tion), Fig. 96, 183

Sphenoid bone, 83; sinus of the,
162; effect on the face of the,
170

Sphenoid sinus, connection with
nasal meati, Fig. 85, 163

Sphenodon, head of, Fig. 23, 42

Sphenodon, see also Hatteria

Sphincter colli, as origin of facial
muscles, 43, 44; of Echidna,
Fig. 23, 42; of Sphenodon,
Fig. 23, 42; migration of, 132

Splenial bone, evolution of, Fig.
52, 82; reduction of, 88; of
Megahchthys, Fig. 64, 111; of
Trimerorhachis, Fig. 64, 111

Spiracle, of shark, Fig. 6, 13, Fig.
81, 155

Squamosal bone, meniscus be-
tween dentary and, in embryo
Perameles, Fig. 22, 38; socket
of lower jaw in the, 39;
evolution of, Fig. 52, 82;
contact with ascending ramus
of dentary in mammals, 87,
108, 109; fused with periodic
mass in mammals, 88; only
remnant of temporo-mandi-
bular series in mammals, 88

Squid, eye of, Fig. 94, 179;
comparison of eyes of, with
those of vertebrates, 179,
180

Stapes, of human ear, Fig. 103,
203, Fig. Ill, 216; derivation
of the, 215; of frog, Fig. 106,
208; of Permocynodon, Fig.
112, 217; of foetal armadillo,
Fig. 114, 221; of human
embryo, Fig. 115, 221

Starfish (Bipinnaria), larva of,
Fig. 55, 93

Stegocephalians, teeth of the, 115

Stensio, Erik A.: Son, cited on
ostracoderms, 10-12, 94, 97,
98; on cyclostomes, 97, 98

Stereoscopic vision, of anthropoid
apes, 65; of human eye, 189

Stockard, Charles R., studies on
growth, 172, 231, 238; on
abnormal human and animal
types, 230; classification of
human faces, 232; description
of linear and lateral types,
233-236; Fig. 117, 232; Fig.
118, 234; on crossing of
linear and lateral types, 237

Studnicka, F. K., evolution of
vertebrate eye figured by,
Fig. 97, 185; cited on embry-
ology of eye in lampreys, 186

Sturgeon, embryo, hyoid gill clefts
in, 209, Fig. 107, 209

Suboperculum, elimination of, Fig.
17, 30, 114

Sudoriparous glands, origin and
function of, 41

Supraoccipital, membranous part
of the, 83

Supratemporal bone, evolution of,
Fig. 49, 79; reduction of, 88;
loss of, by reptiles, 89

Surangular bone, evolution of,
Fig. 52, 82; reduction of, 88;
of Megalichthys, Figs. 64, 111;
of Trimerorhachis, Fig. 64,
111; of turtle embryo, Fig.
64, 111

Sweat glands (sudoriparous),
origin and function of, 41

Swede, Nordic, face of, Fig. 90,
facing 172

Sylvan life, assisted divergent
evolution of primates, 57

Symmetry, radial, gives way to
bilateral, 6

Tabular bones, evolution of, Fig.
49, 79; disappearance in
mammals of, 86

Talgai man, skull of, Fig. 42, 68,
72; muzzle of, 143

Tarsioid stock, platyrrhine monk-
eys as offshoot from some
primitive, 56

Tarsius (the Spectral Tarsier),
Fig. 31, facing 53; mammalian
teeth from Basal Eocene of
Montana related to, 53; top
view of skull of, Fig. 35, 58;
eyes and orbits of, 60, 196

291

INDEX

Tasmanian aborigines, face of,
frontispiece; noses of, 169

Taste organs, of sharks, 16

Tatusia, foetal auditory ossicles in,
Fig. 114, 221

Tear ducts, Fig. 101, 194; glands,
194

Teeth, evolution of mammalian
teeth made possible by change
in articulation of jaw, 39;
anthropoid food and, 57;
human diet and, 57; traces of
derivation from primitive an-
thropoid stage of human, 58;
diagrammatic history of
primate, Fig. 37, 61; evolu-
tion of primate, 63; identity
of human and anthropoid
molar patterns, 69; changes
in teeth of primitive man,
76; pro-mammalian reduction
of successional teeth to two
sets, 90; true teeth lacking in
predecessors of vertebrates,
97; of higher vertebrates,
origin in shagreen denticles,
100; origin of, uncertain
below ostracoderm grade,
101; of herbivores, not an-
cestral to carnivorous types,
101; labyrinthodont pattern
of, Fig. 18, following 30, 112;
gradual elimination of, in
upper primary jaw, Fig. 53,
85, 115; summary of early
history of, 117; embryonic
development of, 134; three
stages in development of
human, Fig. 71, 135; alleged
"triconodont" stage in hu-
man, 136; differences between
human and anthropoid, 141;
reduction of front teeth in
man foreshadowed in fcetal
stages, 143; reduction of,
factor in shortening palatal
arch, 143; effect of civilization
on human, 149; numbers of,
in man and anthropoids, 145;
comparison with those of
Dryopithecus and Sivapithe-
cus, 149; nose form and, Fig.
89, facing 170, 169; incisors,
human, 136; three types of
upper central, 138, Fig. 73,

139; canines, dog-toothed
type of predatory animals,
115; souvenirs of carnivorous
ancestry, Fig. 50, 80, 136;
"feminized" aspect of hu-
man, 141; diminution of
human lower, 144; in func-
tional alignment with incisors
in man, 144; premolars, front
lower, of anthropoids, 144;
human, history of, 146;
molars, of anthropoids, 57;
comparison of human and
cynodont, 145; kinship of
human and anthropoid, 146;
human, history of, 146; fovea
anterior of, in anthropoids
and primitive man, 149; fovea
posterior of, in anthropoids
and primitive man, 149;
lower, 149; "cruciform pat-
tern" of, Fig. 80, 151; "Dry-
opithecus pattern" of lower,
149, Fig. 79, 150
of amphibians, 31
of Australian aboriginal, Fig.

80, 151
of chimpanzee, Fig. 74, 140;

Fig. 79, 150
of crossopts, on dentary, 108;
origin of, 109; structure of
fossil, Fig. 18, following 30,
112; attachment to derm
bones, 112; advance toward
higher vertebrates of, 113;
origin of larger teeth of,
117
of cyclostomes, 98, Fig. 60, 99
of cynodonts, Fig. 53, 85, 115;
mammal-like dentition, 116
of Cynognathus, Fig. 77, 147
of Deltatheridium, Fig. 77, 147
of Diademodon, Fig. 77, 147
of Didelpkodus, Fig. 77, 147
of Dryopithecus, rhenanus, Fig.
38, 62; fontani, Fig. 75, 144,
Fig. 79, 150; cautleyi, Fig. 75,
144, Fig. 79, 150; frickce,
Fig. 41, facing 66; Fig. 79,
150
of Ehringsdorf man, see Man,

Neanderthal
of Egyptian, Fig. 72, 137
of Eoanthropus, Fig. 37, 61, Fig.
38, 62, Fig. 41, facing 66, 72,

292

INDEX

Teeth — (Continued)

141, 143; see also Piltdown

man
of ganoids, 23, Fig. 18, following

30
of gorilla, Fig. 72, 137, Fig. 74,

140, Fig. 79, 150; of gorilla
child, Fig. 76, 146

of Heidelberg man, 143, Fig. 37,

61, Fig. 80, 151
of Hindu, modern, Fig. 80, 151
of Homo heidelbergensis, see

Heidelberg man
of Homo neanderthalensis, see

Neanderthal man
of Homo sapiens, Fig. 37, 61,

Fig. 38, 62, Fig. 72, 137, Fig.

74, 140, Fig. 75, 144, Fig.

76, 146, Fig. 78, 148, Fig. 80,

151
of Indrodon, Fig. 38, 62
of lamprey, 98, Fig. 60, 99
of Leipsanolestes, Fig. 38, 62
of Loxomma allmani, Fig. 18,

following 30
of Michrochoerus, Fig. 78, 148
of Mycterosaurus, Fig. 77, 147
of Neanderthal man (Ehrings-

dorf), Fig. 72, 137, Fig. 75,

144, Fig. 80, 151
of Neanderthal man (Le Mous-

tier), Fig. 38, 62, Fig. 72,

137, Fig. 74, 140, Fig. 78, 148,

Fig. 80, 151
of orang, Fig. 79, 150
of pantotherian (pro-placental,)

Fig. 77, 147
of Parapithecus, Fig. 37, 61
of Pelycodus, Fig. 37, 61
of Piltdown man, 72; canine of,

141, 143; Fig. 37, 61, Fig.
38, 62, Fig. 41, facing 66;
see also Eoanthropus

of placental mammals, 52, 53
of Polyplocodus, Fig. 18, follow-
ing 30
of Pronycticebus, Fig. 78, 148
of Propliopithecus, Fig. 37, 61
of Scylacosaurus, Fig. 77, 147
of Seymouria, 118
of shark, most primitive
(Chlamydoselachus), Fig. 5,
facing 12; origin of, from
shagreen, 19; three stages in
development of, Fig. 60, 99;

nearer to those of man than
to any known teeth of
invertebrates, 102; develop-
ment of, 100; in typical
sharks, 109; not separately
connected with jaws, 109;
manner of replacement of,
117
of Sivapithecus, Fig. 37, 61;

Fig. 75, 144
of reptiles, Fig. 53, 85; pro-
progressive changes in, 115
of triconodont mammals, 136

Temporal bone, socket of lower
jaw in, 39; squamous part of,
83; genesis of, in anthropoids
and man, 88.

Temporal fossa, foreshadowed in
Mycterosaurus, 34; first ap-
pearance of, Fig. 48, 78, 116;
of Scymnognathus and Icti-
dopsis, Fig. 20, 35; origin of,
89; later development of, 90

Temporal muscle, relation to
development of temporal fos-
sa, Fig. 48, 78, 116; evolution,
of, Fig. 61, 103

Temporal region of skull, effect
on the face of, 170

Temporo-mandibular articula-
tion, 87

Temporo-mandibular series, re-
duction of, Fig. 52, 82, 88

Tenrec, of Madagascar, 52.

Tessera, primitive mouth of, Fig.
1, 5

Tetrapods, bony mask of the
earliest, 28

Therapsids, Icfidopsis, skull of,
Fig. 20, 35; Scymnognathus,
skull of, Fig. 20, 35.

Theromorph reptiles, see Reptiles,
mammal-like

Thylacinus (Marsupial Wolf),
dentary of, Fig. 21, 37; skull
of (under side) Fig. 53, 85

Thymus gland, origin in branchial
arches of, 126

Thyroid gland, origin in branchial
arches of, 126; effects of
deficiency in, 171, 237; effect
on growth of face of, 232

Tilney, Frederick, on evolution of
primate brain, 63

Tongue, possible part in develop-

293

INDEX

Tongue — (Continued)

ment of secondary palate,
119; lacking in Amphioxus,
123; of hags and lampreys,
123; of shark, 123; of amphi-
bians, 123; of mammals, 123;
of early and higher primates,
123; papillae vallatae of, in
orang and man, 123; figured
by Klaatsch, 124; of young
gorilla, Fig. 67, 124; of man,
Fig. 67, 124; Fig. 68, 125;
of monkey, Fig. 68, 125;
muscles of, in anthropoids
and man, 125; Robinson
cited on, 126; influence of
human, on evolution of lower
jaw, 126; in human embryo,
123

Tonsils, origin in branchial arches,
126

Tooth-bearing plates, primary
jaws in mammals supplanted
by, 104

Tornaria, larva of Balanoglossus,
Fig. 55, 93

Tragus, little known of origin of,
211; development of the, 212

Tree-shrew, pen-tailed, Fig. 30,
facing 52; of Indo-Malayan
region, apparent relation to
Basal Eocene mammals of
Montana, 53; (Cretaceous)
Leipsanolestes siegfriedti, jaw
of, Fig. 37, 61; left lower
molar of, Fig. 38, 62; In-
drodon, left upper molar of,
Fig. 38, 62

Tremataspis, Fig. 4, 11; character-
istics of mouth of, 96

Triassic, Ictidopsis of, frontispiece;
Fig. 28, 49; hair of mammals
possibly developed during,
42; labyrinthodonts and steg-
ocephalians of, 115; mam-
mal-like reptiles of the, 158

Triconodont mammals, teeth of,
136

Trilobites, mouth-legs of, 6

Trimerorhachis, lower jaw of, Fig.
64, 111

Trinil man, see Pithecanthropus

Turbinal bones, early structures
resembling, 158; in monkeys
and man, 161

Turtle, lower jaw of embryo, Fig.
64, 111

Tympanic membrane, 202; Fig.
103, 203

Tympanum, formation by amphi-
bians, 89; Fig. 17, 30, 216; of
human ear, 202; Fig. 103„
203; Fig. Ill, 216

Tyrolese, nose of, Fig. 89, 170

Ultra-violet rays, injurious effect
on many organisms, 174

Utriculus, of human ear, 202; Fig.
103, 203

Vertebral column, evolution of
primate, 63

Vertebrates, derivation of, 5;
Patten's theory of derivation
of, 7, 92, 182; orthodox
theory of derivation of, 7, 93;
period of origin of, 8; changed
heritage of, 10; antiquity of,
10; predaceous ancestry of, 12;
jaws of earliest landliving,
25; real ancestors of the
higher, 25; inheritance of
framework of face from lower,
91; characters of ancestors of,
93; origin of mouth of, 94,
Fig. 56, 94; organization of,
adapted to predaceous mode
of fife, 101; potentialities of
skin in ancestors of, 100, 101;
gill pouches of embryos of
higher, 102; derivation of jaw
muscles of, Fig. 61, 103, 104;
primary upper jaw of, at-
tached to skull, 104, Fig. 62,
105; primary jaws masked by
secondary, 106; secondary
jaws as evidence of unity of
origin of all, 107; branchial
skeleton of, compared with
human, 128; eyes of inverte-
brate compared with eyes of,
178; origin of paired eyes of,
178; Patten's theory of de-
rivation of eyes of, 182;
evidence of embryology on
origin of eye of, Fig. 97, 185,
186; Eustachian tube in
higher, 208

Viscera, of Primates, results of
study of, 63

294

INDEX

"Visceral arches," architecture
of, 104; in predecessors of the
sharks, 104
Vision, the mechanism of, 189;
binocular, of Old World
monkeys, anthropoids and
man, 196; binocular, not
possible in Notharctus, 196;
developed by brachiating
habit, 198
Visual cortex of brain, 191
Visual purple (rhodopsin), 189
Vitreous humor, of the eye, 188
Vomer, 83

Watson, D. M. S., studies of fossil
amphibia, 28; restoration of
skeleton of Eogyrinus from
data of, 28; contributions to
palaeontology, 86

Weber, Max, evidence for con-
clusions on ancestry of
placental mammals, 51

Williams, J. Leon, cited on three
types of central upper in-
cisors, 138, Fig. 73, 139

Williston, S. W., contributions to
palaeontology, 86

Williston's law, illustrated, Figs.
48-52, 78-82; loss of oper-
cular series, example of, 114

Wolf, marsupial (Thylacinus),
under side of skull of, Fig.
53, 85; dentary of, Fig. 21, 37

Worm, annelid, head of, 6; flat-
worm, 6, Fig. 2, facing 6

Wyoming, Notharctus found in
Eocene formations of, 54

Yerkes, R. M., cited on agreement
of mental traits in man and
anthropoid, 74; Fig. 39 copied
from photograph by, facing 64

Zalambdalestes, skull and restora-
tion of head, Fig. 29, 50

Ziska, Mrs. Helen, drawings made
by, 86

Zygomatic arch, foreshadowed in
Mycterosaurus, 34; origin of
human, 89

295

?39E-n 7 4MEL,

Library Bureau Cat.no. 1137

CLAPP

3 5002 00370 0262

Gregory, William K.

Our face from fish to man; a portrait ga

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