THE APODOUS HOLOTHUEIANS 7 



Morphology (continued). ^^^^ 



Calcareous Deposits 140 



Tables 140 



Shallow, closed Cups 141 



Perforated Plates 141 



Fusiform Bodies 141 



Anchors 143 



Phosphatic Deposits 142 



Transverse Muscles 143 



Longitudinal Muscles 144 



Inner Epithelium 144 



Body-cavity 144 



Calcareous Ring 145 



Water-vasciilar System 145 



Alimentary Canal 148 



Respiratory Trees 149 



Cuvier's Organs 150 



Blood System 150 



Reproductive System 151 



Embryology 153 



Physiology 152 



Motion 152 



Digestion and Absorption 152 



Circulation and Nutrition 152 



Respiration 153 



Excretion . . . .' 154 



Sensation 154 



Regeneration 15-4 



Reproduction 154 



Ecology 154 



Taxology 155 



Key to the Genera of Molpadiida; 156 



Molpadia 15G 



Caudina 172 



Acaudina I'i'S 



Eupyrgus 179 



Aphelodactyla ISO 



Ceraplectana 183 



Himastlilephora 184 



Gephyrothuria 185 



Concluding Remarks on the Molpadiidae 186 



Interrelationships 186 



Geographical Distribution 187 



Bibliography 190 



Explanation of Plates 207 



Index 327 



