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TABLE OF CONTENTS 



PAGE 



LIST OF TEXT-FIGURES ......... vii 



INTRODUCTION . . . . . . . . . . . xi 



HISTORICAL ACCOUNT OF THE CHAETOPODA, WITH SPECIAL REFERENCE 



TO THE POLYCHAETA AND THEIR CLASSIFICATION .... 1 



ARENICOLIDAE ........... 25 



ARENICOLA Lamarck, emend. . . . . . . .29 



A General Account of the Genus Arenicola .... 32 



External Characters ....... 33 



External Apertures ........ 38 



Chaetae . . . 39 



Gills 55 



Coelom and Coelomic Septa . . . . .61 



Alimentary Canal : Burrowing ...... 63 



Nervous System and Sense-Organs ..... 66 



Nephridia ......... 71 



Reproductive Organs ....... 72 



Development ......... 73 



Post-Larval Stages, with a Discussion of the Genus Clymenides . 75 

 Post-Larval Stages of A. marina ..... 77 



,, ,, ,, A. cristata ..... 79 



,, ,, ,, A. assimilis var. affinis ... 80 



,, ,, A. ecaudata ..... 80 



,, ,, A. branchialis . . . , .81 



Separation of the Genus Arenicola into Sections and Species . 82 

 The Caudate Section of the Genus Arenicola (with a Key to the 

 Caudate Species) * .- . . . . . .83 



The Ecaudate Section of the Genus Arenicola (with a Key to 

 the Ecaudate Species) ....... 84 



Arenicola marina (Linnaeus) . . . . . .86 



Arenicola loveni Kinberg, emend. . . . . . 103 



Arenicola cristata Stimpson . . . . . . 105 



Arenicola glacialis Murdoch . . . . . . Ill 



Arenicola pusilla Quatrefages . . . . ^''iJA 

 Arenicola assimilis Ehlers, and var. affinis Ash worth. . /' 123 

 Arenicola ecaudata Johnston . . . . . .132 



Arenicola branchialis Audouin and Edwards . . . 138 

 BRANCHIOMALDANE Langerhans ....... 147 



Branchiomaldane vincenti Langerhans ..... 147 



THE INTER-RELATIONSHIPS OF THE MEMBERS OF THE FAMILY ARENICOLIDAE 156 

 THE AFFINITIES OF THE ARENICOLIDAE ...... 159 



SYSTEMATIC INDEX TO THE ARENICOLIDAE ...... 163 



GENERAL INDEX ........... 165 



DESCRIPTION OF PLATES I-XV . . . 171 



