CONTENTS XV 



PAGE 



XII. The Sensory Organs . 462 



A. The Ambulaoral Appendages as Sensory Organs 462 



B. Nerve Endings in the Integument . 466 



C. Auditory Organs, Organs op Orientation . 468 



D. Eyes . . .468 



XIII. The Body Musculature 470 



A. HOLOTHURIOIDEA . 471 



B. EOHINOIDEA 471 



C. ASTEROIDEA 472 



D. OPHIUEOIDEA 474 



E. Crinoidea . 474 



XIV. The Alimentary Canal 474 



A. General Review 474 



B. HOLOTHUBIOIDEA 476 

 0. EOHINOIDEA 479 



D. Crinoidea . 481 



E. Asteeoidea 483 



F. Ophiueoidea 485 



XV. Respiratory Organs 485 



A. The (inner) Respiratory Trees of the Holothurioidea . 487 



B. Eeview of the Respiratory Organs of the Echinoder- 



mata . . 487 



XVI. The Cuvibeian 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. Ophiueoidea 494 



1. The Burs^ . . 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 foe Regeneeation and Asexual Repeoduction 504 



XXI. Ontogeny ..... 506 



A. The Various Larval Forms of the Eohinodeemata 506 



