The Evolution of Man, vol 2 | Page 2

HUMAN BRAIN.
FIGURES 2.294 TO 2.296. CENTRAL MARROW OF HUMAN
EMBRYO.
FIGURE 2.297. HEAD OF A CHICK EMBRYO.
FIGURE 2.298. BRAIN OF THREE CRANIOTE EMBRYOS.
FIGURE 2.299. BRAIN OF A SHARK.
FIGURE 2.300. BRAIN AND SPINAL CORD OF A FROG.
FIGURE 2.301. BRAIN OF AN OX-EMBRYO.
FIGURES 2.302 AND 2.303. BRAIN OF A HUMAN EMBRYO.
FIGURE 2.304. BRAIN OF THE RABBIT.
FIGURE 2.305. HEAD OF A SHARK.
FIGURES 2.306 TO 2.310. HEADS OF CHICK-EMBRYOS.
FIGURE 2.311. SECTION OF MOUTH OF HUMAN EMBRYO.
FIGURE 2.312. DIAGRAM OF MOUTH-NOSE CAVITY.
FIGURES 2.313 AND 2.314. HEADS OF HUMAN EMBRYOS.
FIGURES 2.315 AND 2.316. FACE OF HUMAN EMBRYO.
FIGURE 2.317. THE HUMAN EYE.
FIGURE 2.318. EYE OF THE CHICK EMBRYO.
FIGURE 2.319. SECTION OF EYE OF A HUMAN EMBRYO.
FIGURE 2.320. THE HUMAN EAR.
FIGURE 2.321. THE BONY LABYRINTH.
FIGURE 2.322. DEVELOPMENT OF THE LABYRINTH.

FIGURE 2.323. PRIMITIVE SKULL OF HUMAN EMBRYO.
FIGURE 2.324. RUDIMENTARY MUSCLES OF THE EAR.
FIGURES 2.325 AND 2.326. THE HUMAN SKELETON.
FIGURE 2.327. THE HUMAN VERTEBRAL COLUMN.
FIGURE 2.328. PIECE OF THE DORSAL CORD.
FIGURES 2.329 AND 2.330. DORSAL VERTEBRAE.
FIGURE 2.331. INTERVERTEBRAL DISK.
FIGURE 2.332. HUMAN SKULL.
FIGURE 2.333. SKULL OF NEW-BORN CHILD.
FIGURE 2.334. HEAD-SKELETON OF A PRIMITIVE FISH.
FIGURE 2.335. SKULLS OF NINE PRIMATES.
FIGURES 2.336 TO 2.338. EVOLUTION OF THE FIN.
FIGURE 2.339. SKELETON OF THE FORE-LEG OF AN
AMPHIBIAN.
FIGURE 2.340. SKELETON OF GORILLA'S HAND.
FIGURE 2.341. SKELETON OF HUMAN HAND.
FIGURE 2.342. SKELETON OF HAND OF SIX MAMMALS.
FIGURES 2.343 TO 2.345. ARM AND HAND OF THREE
ANTHROPOIDS.
FIGURE 2.346. SECTION OF FISH'S TAIL.
FIGURE 2.347. HUMAN SKELETON.
FIGURE 2.348. SKELETON OF THE GIANT GORILLA.
FIGURE 2.349. THE HUMAN STOMACH.
FIGURE 2.350. SECTION OF THE HEAD OF A
RABBIT-EMBRYO.
FIGURE 2.351. SHARK'S TEETH.
FIGURE 2.352. GUT OF A HUMAN EMBRYO.
FIGURES 2.353 AND 2.354. GUT OF A DOG EMBRYO.
FIGURES 2.355 AND 2.356. SECTIONS OF HEAD OF LAMPREY.
FIGURE 2.357. VISCERA OF A HUMAN EMBRYO.
FIGURE 2.358. RED BLOOD-CELLS.
FIGURE 2.359. VASCULAR TISSUE.
FIGURE 2.360. SECTION OF TRUNK OF A CHICK-EMBRYO.
FIGURE 2.361. MEROCYTES.
FIGURE 2.362. VASCULAR SYSTEM OF AN ANNELID.
FIGURE 2.363. HEAD OF A FISH-EMBRYO.
FIGURES 2.364 TO 2.370. THE FIVE ARTERIAL ARCHES.

FIGURES 2.371 AND 2.372. HEART OF A RABBIT-EMBRYO.
FIGURES 2.373 AND 2.374. HEART OF A DOG-EMBRYO.
FIGURES 2.375 TO 2.377. HEART OF A HUMAN EMBRYO.
FIGURE 2.378. HEART OF ADULT MAN.
FIGURE 2.379. SECTION OF HEAD OF A CHICK-EMBRYO.
FIGURE 2.380. SECTION OF A HUMAN EMBRYO.
FIGURES 2.381 AND 2.382. SECTIONS OF A CHICK-EMBRYO.
FIGURE 2.383. EMBRYOS OF SAGITTA.
FIGURE 2.384. KIDNEYS OF BDELLOSTOMA.
FIGURE 2.385. SECTION OF EMBRYONIC SHIELD.
FIGURES 2.386 AND 2.387. PRIMITIVE KIDNEYS.
FIGURE 2.388. PIG-EMBRYO.
FIGURE 2.389. HUMAN EMBRYO.
FIGURES 2.390 TO 2.392. RUDIMENTARY KIDNEYS AND
SEXUAL ORGANS.
FIGURES 2.393 AND 2.394. URINARY AND SEXUAL ORGANS
OF SALAMANDER.
FIGURE 2.395. PRIMITIVE KIDNEYS OF HUMAN EMBRYO.
FIGURES 2.396 TO 2.398. URINARY ORGANS OF
OX-EMBRYOS.
FIGURE 2.399. SEXUAL ORGANS OF WATER-MOLE.
FIGURES 2.400 AND 2.401. ORIGINAL POSITION OF SEXUAL
GLANDS.
FIGURE 2.402. UROGENITAL SYSTEM OF HUMAN EMBRYO.
FIGURE 2.403. SECTION OF OVARY.
FIGURES 2.404 TO 2.406. GRAAFIAN FOLLICLES.
FIGURE 2.407. A RIPE GRAAFIAN FOLLICLE.
FIGURE 2.408. THE HUMAN OVUM.

CHAPTER 2.
16. STRUCTURE OF THE LANCELET AND THE SEA-SQUIRT.
In turning from the embryology to the phylogeny of man--from the
development of the individual to that of the species--we must bear in
mind the direct causal connection that exists between these two main
branches of the science of human evolution. This important causal
nexus finds its simplest expression in "the fundamental law of organic

development," the content and purport of which we have fully
considered in the first chapter. According to this biogenetic law,
ontogeny is a brief and condensed recapitulation of phylogeny. If this
compendious reproduction were complete in all cases, it would be very
easy to construct the whole story of evolution on an embryonic basis.
When we wanted to know the ancestors of any higher organism, and,
therefore, of man--to know from what forms the race as a whole has
been evolved we should merely have to follow the series of forms in
the development of the individual from the ovum; we could then regard
each of the successive forms as the representative of an extinct
ancestral form. However, this direct application of ontogenetic facts to
phylogenetic ideas is possible, without limitations, only in a very small
section of the animal kingdom. There are, it is true, still a number of
lower invertebrates (for instance, some of the Zoophyta and Vermalia)
in which we are justified in recognising at once each embryonic form
as the historical reproduction, or silhouette, as it were, of an extinct
ancestor. But in the great majority of the animals, and in the case of
man, this is impossible, because the embryonic forms themselves have
been modified through the change of