XH TABLE OF CONTENTS. 



SpawnlMC scnson — CnnfimiPtl. Page. 



Compsometra lovfni __ STo 



CocconiPtra nigrolino;!f:i 373 



noccODietni hagenii 373 



I'sntbyrouietra fragllis 373 



liPptonietra phalangium 373 



Ilathroiiiefra sarsii ——,__— — _ 374 



rontaiiiPti'ocrinns tuborculatus . — 1-- 374 



Pentiuiietrocrimis japouicus 374 



Pentaniotrocrinus varians 374 



Copulation 375 



Passage of the spermatozoa into (lie receptaculum seminis in Isometra vivipara 375 



Development of the eggs 375 



Growth of the oocyte —_——-—-__-__- 377 



Ripening of the eggs I____l 1__ 408 



Extrusion of the eggs 408 



Egg ease 409 



Eggs 410 



Regeneration 410 



Possible extent of regeneration 414 



Influence of different factors on regeneration 416 



Color of regenerating parts 417 



Visceral mass 417 



Details of arm regeneration 424 



Closure of the wound and degeneration of the cell elements 424 



Rebuilding of the water tube and of the coeloniic canal 426 



Dorsal and ventral nervous systems 427 



Genital cord 429 



Muscles and ligaments 429 



Skeletal structures 430 



Details of the regeneration of the cirri _ 430 



Embryology and development 431 



Cleavage ._„___, 433 



Gastrulatiou rr,-,--— 436 



Closure of the blastopore '. 439 



Division of the primitive gut into mesenteron, peritoneal sac, and iirimary hydroerele-, 440 

 Formation of ciliated hands, larval nervous system, and alteration in position of in- 

 ternal organs (60 to S4 hours) 443 



Last period of embryonal development; formation of calcareous skeleton (48 to 120 



hours) 447 



Free swimming larva 450 



Ectoderm 450 



Ectodermal epithelium, ciliated bands, and intermediate areas 450 



Apical pit and nervous system 452 



Attachment dislj and vestibular invagination 454 



Intestinal canal , 455 



Coelome and chambered organ 456 



Hydrocoele and parietal canal 459 



Mesenchyme 461 



Attachment of larva and its transformation into stalked form ^,^-^ „^^ 463 



Description of larva up to fifth day after escape from egg membrane ^-^-,-r--— 463 



EJctoderm 4g4 



Vestibule 465 



