CONTKNTS. 



XI 



Chaptkh XXXVI. CEPHALOCHORDA (AMPHIOXUS). By K. 



Heider 535. 



Amphioxus 535 



A, Oviposition, cleavage and gastrulati on .... 535. 



/.'. Development of the medullary tube, the primitive seg- 

 ments and the notochord ...... 539 



( '. Further development up to the time when the mouth 



and the first gill-cleft form 544 



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



1 reneral considerations on Amphioxus ...... 571 



Literature 580 



Subjects Index 

 Authors Index . 



585- 

 58it 



