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another, and the organ may undergo structural modification in
consequence. Examples of change of function: the wing of the
bat; lungs and swimming bladders; electric organs of fish.

Other Objections. Insufficiency of Time. Evidence of Design and
Forethought. Instinct.

LECTURE VII. (Pp. 173-199.)

THE ORIGIN OF VERTEBRATED AMIMALS.

The evidence available for the determination of genetic affinities is
of three chief kinds :-

1. That afforded by comparison of structure.

2. That afforded by development.

3. That afforded by fossils.

THE CRANIATE VERTEBRATES.

The Zoological characters of the higher Vertebrates. The brain
and spinal cord; the vertebral column and skull.

The characters of Fish and Amphibians. The mutual relations of
the two groups. The transition from the water-breathing to
the air-breathing condition. The evolution of lungs.

The Zoological characters of Reptiles, Birds, and Mammals. The
relations of these groups to Fish and Amphibians. Evidence
in favour of the descent of Reptiles, Birds, and Mammals from
aquatic ancestors.

The mutual relations of Reptiles and Birds. The special characters
of Birds. Fossil forms intermediate between the two groups.
Embryological evidence. The development of the pelvic girdle.

The special characters of Mammals. The development of Mammals.
Indications of the former presence of large eggs. The eggs of
Echidna. Palæontological evidence in favour of the descent of
Mammals from Reptiles.

THE ACRANIATE VERTEBRATES.

The Anatomical and Embrylogical characters of Amphioxus. Re-
lation of Amphioxus to other Vertebrates.

The characters of Ascidians. Supposed ancestral relations to other
Vertebrates. The development of Ascidians. Evidence of
degeneration. Evidence in favour of a pelagic marine ancestry
for all Vertebrates. Supposed relations with Invertebrates.

"The Power of Movement in Plants"
"Vegetable Mould and Earthworms"

Death

1880.

1881.

19th April, 1882.

The Darwin Family: Erasmus Darwin, 1731-1802: author of
"Zoonomia," and grandfather of Charles Darwin.

Life of Charles Darwin: School and College career; found lectures
"intolerably dull." The Voyage of the Beagle, 1831-1836;
Outline of the Voyage; its purpose and its results; its influence
on Darwin-" by far the most important event in my life."
Return to England: lived for nearly six years in London. In
1842 settled at Down, near Beckenham, where the greater part
of his work was accomplished, and the rest of his life spent.

Darwin's Work: The Beagle Reports, 1840-1846; the Theory of the
Structure and Distribution of Coral Reefs, 1842. The Mono-
graph on the Cirripedia, 1846-1854.

The "Origin of Species." Preliminary Work; unwillingness
to publish until completed. Independent discovery of Natural
Selection by Darwin and Wallace. Influence of Malthus' Essay
on Population. "The chief work of my life."

Darwin's later works, "The Descent of Man," and "Expres-
sion of the Emotions." The great series of Botanical works.

Personal Characteristics: Daily life and habits. Chronic ill-health.
System of work: Direct observation and experiment: Simple
methods and few instruments: Dogged industry. His last book,
"Vegetable Mould and Earthworms," considered as a sample
of his mode of work. Darwin's estimate of his own powers:
"My mind seems to have become a kind of machine for grind-
ing general laws out of large collections of facts." Avoidance
of controversy. Darwin's influence on Scientific Thought. The
great importance of little things.

INDEX

Pp. 229-236

FIG.

LIST OF ILLUSTRATIONS

ARCHÆOPTERYX. (From a photograph of original specimen)

PAGE

Nature, and lent by W. E. HOYLE, Esq.)

Frontispiece

}

I. DOMESTIC PIGEONS) (From drawings made for the Author by 2. DOMESTIC FOWLS R. E. HOLDING)

26, 32

3. GALLUS BANKIVA, The Jungle-Fowl. (Photographed from

[blocks in formation]

4 & 5. DENTALIUM and LINGULA (after NICHOLSON)

58

64

66

80

9. PRAWN, Development of. (From a drawing by the Author,

6. PHENACODUS (after COPE)

7. FLYING REPTILE, Diagram. (From a drawing by the Author) 8. ASCIDIAN AND FROG TADPOLES (after LANKESTER)

after FRITZ MULLER)

10. BARNACLE, Development of. (From a drawing by the Author, after SPENCE BATE)

II. SACCULINA, Development and Degeneration of. (From a drawing by the Author: A, B, and C after Delage; D from Nature)

12. Flounder, Young and Adult Specimens. (From a drawing by the Author: A and B after CUNNINGHAM; C after BUCKLAND and COUCH)

13. CRAB, Young and Adult Specimens. (From a drawing by the Author: A after Weldon; B after CLAUS; C after BELL) 14. ORBITOLITES AND PENEROPLIS (From a drawing by the Author, after BRADY and CARPENTER)

81

82

83

86

90

92

15. FROG AND TADPOLES. (From a drawing by the Author from Nature)

100

16. HYLODES, Young and Adult Specimens. (From a drawing by the Author, after BREHM)

101

17. EYES OF SOLEN, HALIOTIS, PATELLA AND FISSURELLA. (From a drawing by the Author)

108

18. DIAGRAM OF EYES OF PATELLA, HALIOTIS AND FISSURELLA. (From a drawing by the Author).

109

FIG.

PAGE

19. LOLIGO, Adult Specimen, and Development of Eye. (From a drawing by the Author, after LANKESTER)

110

20. AMPHIOXUs, Adult Specimen and early Developmental Stages. (From a drawing by the Author, after HAT

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21. MONAD, PANDORINA, SALINELLA AND VOLVOX. (From a drawing by the Author, after Frenzel and others)

114

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25. METHONA AND LEPTALIS. (Photographed from Nature)

138

26. BIRD OF PARADISE. (Photographed from Nature, and lent by

W. E. HOYLE, Esq..

142

27. ORCHIS MASCULA. (From a drawing by the Author, after DARWIN and OLIVER)

146

28. PTEROPUS. (From a drawing made for the Author by R. E.

HOLDING)

165

29. DIAGRAM to show the evolution of the lung from the swim-bladder of fish. (From a drawing by the Author)

167

30. ICHTHYOSAURUS

(after THOMAS HAWKINS)

178, 179

31. PLESIOSAURUS

33. ECHIDNA

}

32. OrnithorhYNCHUS) (From drawings made for the Author by

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34. EMBRYO CHICK. (From a drawing by the Author from Nature) 35. CLAVELINA. (From a drawing made by Walter GaRSTANG,

186

Esq.)

190

36. PRIMULA. (From a drawing by the Editor)

218

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