CONTENTS 



PREFACE vii 



INTRODUCTORY AND HISTORICAL 1 



1 THE NATURE AND CRITERIA OF SENESCENCE 



1 • 1 The Measurement of senescence 1 7 



1 -2 Forms of senescence 33 



1-2-1 Mechanical senescence 34 



1-2-2 'Accumulation' and 'depletion' 35 



1-2-3 Morphogenetic senescence 



36 



1 -3 Senescence in evolution 37 



2 THE DISTRIBUTION OF SENESCENCE 



2-1 Character of the evidence 42 



2-2 Maximum longevities in animals 45 



2-2-1 Mammals 46 



2-2-2 Birds 49 



2-2-3 Reptiles 51 



2-2-4 Amphibians 52 



2-2-5 Fish 53 



2-2-6 Invertebrates 54 



2-3 Maximum life-span in man 59 



2-4 Distribution of senescence in vertebrates 63 



2-4-1 Fish 68 



2-4-2 Reptiles 77 



2-5 Distribution of senescence in invertebrates 79 



2-5-1 Porifera 80 



2-5-2 Coelenterates 81 



2-5-3 Sundry invertebrates S3 



2-5-4 Rotifers 84 



2-5-5 Arthropods 92 



2-5-6 Molluscs 102 



ix 



71047 



