TABLE OP CONTENTS. 



Page 



Introduction 9 



PART I. 



The Classification of the Apodous Holothurians 11 



Table of Accepted Genera, with Type Species 22 



PART II. 



The Apodous Holotlmrians of the United States National Museum 23 



Synaptidse 23 



Molpadiidffi 31 



PART III. THE SYNAPTIM:. 



Morphology 42 



Form and Size 42 



Color 42. 



Body-surface 43 



Tentacles 44 



Sense-organs 46 



Light-detecting 46 



Positional 46 



Gustatory 46 



Tactile 47 



Nervous System 47 



Body-wall 48 



Epidermis 48 



Connective-tissue Layer 48 



Pigment-cells 48 



Calcareous Deposits 49 



Anchors and Plates 49 



Wheels 50 



Curved Eods 51 



Miliary Granules 51 



Cinrular Muscles 52 



Longitudinal Muscles 52 



Inner Epithelium 52 



Body-cavity 53 



Calcareous King 53 



Cartilaginous King 54 



Water-vascular System 54 



Alimentary Canal 56 



Ciliated Funnels 57 



Blood System 58 



Reproductive System 58 



Embryology 59 



5 



