GENERAL INDEX. xvii 



Page Sec. 



Their power of destroying shell-fish . 177 . 465 



Absorption of nutriment from digestive cavities 178 . 467 



Intestinal veins 178 . 468 



Vascular system of Aster ias . . . ."".'. ^ 178 . 469 



Respiratory function in Asierias 180 . 474 



Madreporic plate and " sand -canal " -. ">\ ~-\ ** : --V '.. '' v . . . 181 . 476 



Ciliary apparatus of Star-fish . . -. -. . . . 181 . 477 



Reproductive system (female) ] 82 . 479 



Male generative organs 182 . 480 



Ova 183 . 481 



Anatomical structure of ovum '. 183 . 481 



Development of embryo 183 . 481 



Growth of young Star-fish, according to the observations of Sars . 183 . 482 



Agassiz 184 . 484 



Miiller's researches relative to the metamorphoses of Ophiurus . . 185 . 487 



Pluteus paradoxus 186 . 488 



Phenomena accompanying its development into a Star-fish . . . 187 . 491 



Development and growth of rays 187 . 492 



Nervous system of Asterias 1 88 496 



Oculiform specks 189 . 497 



General sensibility of the Echinodermata 189 . 497 



ECHINI 190 . 498 



Shell of Echinus 190 . 500 



Necessity for its elaborate construction 191 . 505 



Tubular suckers 192 . 506 



Locomotive spines 193 . 507 



Mode of their articulation with the shell 193 . 507 



Growth of the spines of Echinus 194 . 509 



Internal structure of spines 194 . 510 



Mouth of Echinus 195 . 511 



" Lantern of Aristotle " 196 . 511 



Mechanism and muscular apparatus of the " jaws " 197 . 512 



Digestive system of Echinus 198 . 518 



Circulatory system 199 . 520 



Respiratory function how performed f . . 199 . 522 



Pinnated tentacula 199 . 523 



Nervous system 200 . 524 



Reproductive organs 200 . 525 



Development of embryo 200 . 526 



Miiller's researches Metamorphoses of Echini 200 . 526 



HOLOTHUEIDJS 202 . 531 



Structure of muscular integument * . 202 . 531 



Locomotive suckers 202 . 532 



Digestive system of Holothuria 204 . 533 



Respiratory apparatus 204 . 536 



Circulatory system 206 . 537 



Generative organs 208 . 539 



Metamorphoses of embryo 208 . 540 



Nervous system 209 . 541 



Muscular irritability 209 . 541 



FlSTULARID^E 209 . 542 



Sipunculus 210 . 543 



Cuticle 210 . 545 



Muscular system 210 . 546 



Digestive apparatus 210 . 547 



Vascular system 211 . 550 



Course of the circulation 212 . 551 



Sacculi 213 . 552 



Nervous system 213 . 553 



b 



