CHAPTER III

FLOATING CREATURES OF THE SEA 30

The Nature of Floating Life--Memoir on Medusæ Accepted by the
Royal Society--Old and New Ideas of the Animal Kingdom--What
Huxley Discovered in Medusæ--His Comparison of them with
Vertebrate Embryos


CHAPTER IV

EARLY DAYS IN LONDON 46

Scientific Work as Unattached Ship-Surgeon--Introduction to
London Scientific Society--Translating, Receiving, and
Lecturing--Ascidians--Molluscs and the Archetype--Criticism of
Pre-Darwinian Evolution--Appointment to Geological Survey.


CHAPTER V

CREATURES OF THE PAST 67

Beginning Palæontological Work--Fossil Amphibia and
Reptilia--Ancestry of Birds--Ancestry of the Horse--Imperfect
European Series Completed by Marsh's American Fossils--Meaning of
Geological Contemporaneity--Uniformitarianism and Catastrophism
Compared with Evolution in Geology--Age of the Earth--Intermediate
and Linear Types.