xii CONTENTS. 
CHAPTER XIII. 
C@LENTERATA, 
Hydra 
Obelia 
Actinia 
Alcyonium 
Aurelia 
Cydippe : 
The Ceelenterata ... 
CHAPTER XIV. 
PLATYVHELMINTHES, NEMATHELMINTHES 
AND ROTIFERA., 
Distomum 
Teenia ‘ vis 
The Platyhelminthes 
Hydatina ... s 
The Rotifera 
Ascaris ae 
The Nemathelminthes 
CHAPTER XV. 
ARCHICG@LOMATA. 
Asterias 
Balanoglossus 
Lophopus ... 
Sagitta 
Waldheimia 
The Archiccelomata 
CHAPTER XVI, 
ANNULATA. 
Polygordius 
Arenicola ... 
Hirudo 
Lumbricus 
III 
117 
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127 
131 
133 
137 
144 
142 
151 
152 
152 
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