Contents 



Page 



History 1 



Specimen Deposition 2 



Acknowledgments 3 



Abbreviations Used in the Figures 4 



Methods 4 



Orientation 7 



Segmentation 8 



Common Names 8 



The Burrow 9 



The Mantle 11 



External Mantle Flap in Trypetesa lateralis ... 14 



Digestive System and Feeding Mechanisms .... 17 



The Cirri 19 



FeedingHatoits of Trypetesa lateralis feraalea . . 19 



Excretory System 21 



Muscular System 22 



Circulatory and Respiratory Systems 24 



Reproductive System 24 



The Male 24 



Ultrastructure of the Male and Its Sperm ... 25 



Embryology and Mating Behavior 27 



SexuaUty in the Cirripedia 28 



Conjectures on Sexuality 29 



Systematics and Characteristics 30 



Fossils 134 



Undescribed Fossil Species 141 



Distribution 143 



Key to the Order Acrothoracica 149 



Phylogeny 151 



Literature Cited 155 



Index of Species and Figures 161 



