CONTENTS. XI 



PAGE. 



CHAPTER XXXVI. CEPHALOCHORDA (AMPHIOXUS). By K. 



HEIDEB 535 



Amphioxus , 535 



.4. Ovipositiou, cleavage and gastrulation . . . . 535 



B. Development of the medullary tube, the primitive seg- 



ments and the notochord 539 



C. Further development up to the time when the mouth 



and the first gill-cleft form 544 



D. Later larval stages . . . . . - 551 



General considerations on Amphioxus 571 



Literature 580 



SUBJECTS INDEX 585 



AUTHORS INDEX . 58ti 



