TABLE OF CONTENTS 



PAGK 



LIST OF TEXT-FIGURES . . vii 



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



HISTORICAL ACCOUNT OF THE CHAETOPODA, WITH SPECIAL KEFERENCE 



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 arid Coelomic Septa ...... 61 



Alimentary Canal : Burrowing . . . . .63 



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



Nephridia 71 



Keproductive 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. branchialix ..... 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 . . . . . .111 



Arenicola pusilla Quatrefages . ... . . .114 



Arenicola assimilis Ehlers, and var. affinis Ashworth. . 123 



Arenicola ecaudata Johnston . . . . . . ] 32 



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 



