CONTENTS xv 



PAGE 



XII. THE SENSORY ORGANS ..... 462 



A. THE AMBULACRAL APPENDAGES AS SENSORY ORGANS . 462 



B. NERVE ENDINGS IN THE INTEGUMENT . . . 466 



C. AUDITORY ORGANS, ORGANS OF ORIENTATION . . . 468 



D. EYES ..... .468 



XIII. THE BODY MUSCULATURE ... . 470 



A. HOLOTHURIOIDEA . . 471 



B. ECHINOIDEA . . 471 



C. ASTEROIDEA . ... 472 



D. OPHIUROIDEA ... . . 474 



E. CRINOIDEA .... . . 474 



XIV. THE ALIMENTARY CANAL . . 474 



A. GENERAL REVIEW . . . . . 474 



B. HOLOTHURIOIDEA ... . . 476 



C. ECHINOIDEA . 479 



D. CRINOIDEA . . . . . 481 



E. ASTEROIDEA ....... 483 



F. OPHIUROIDEA ....... 485 



XV. RESPIRATORY ORGANS ...... 485 



A. THE (INNEE) RESPIRATORY TREES OF THE HOLOTHURIOIDEA . 487 



B. REVIEW OF THE RESPIRATORY ORGANS OF THE ECHINODER- 



MATA ........ 487 



XVI. THE CUVIERIAN ORGANS OF THE HOLOTHURIOIDEA . . 488 



XVII. EXCRETION . . 489 



XVIII. THE SACCULI OF THE CRINOIDEA . . . 489 



XIX. GENITAL ORGANS . . 490 



A. GENERAL MORPHOLOGY ... . 490 



B. HOLOTHURIOIDEA . . . 491 



C. ASTEROIDEA . . . 492 



D. OPHIUROIDEA . 494 



1. THE BURSTS ... 494 



2. THE GENITAL APPARATUS . . . . 495 



E. ECHINOIDEA . . 498 



F. CRINOIDEA .... 500 



G. ORIGIN OF THE SEXUAL PRODUCTS . . . 501 

 H. HERMAPHRODITISM IN ECHINODERMS . . . 501 



1. CARE OF THE BROOD AND SEXUAL DIMORPHISM . 502 



XX. CAPACITY FOR REGENERATION AND ASEXUAL REPRODUCTION . 504 



XXI. ONTOGENY ....... 5.06 



A. THE VARIOUS LARVAL FORMS OF THE ECHINODERMATA 506 



