470 



INVEKTEBKATA 



CHAP. 



future star-fish and are termed collectively the aboral disc. As 

 the ventral horn of the left posterior coelom extends further and 



FIG. 362. Lateral views of the brachio- 

 larian phase of the larva of Aster 'i as 

 vulgaris in various stages of fixation 

 and metamorphosis. (After Goto.) 



A, earliest stage : temporary fixation by 

 means of the brachiolarian arms: prae-mal 

 lobe undiminished. B, later stage: permanent 

 iixation by means of the fixing disc: the 

 prae-oral lobe is much shrunk. C, still later 

 stage : the prae-oral lobe has almost dis- 

 appeared : metamorphosis almost complete. 

 Lettering as in Fig. 300. In addition, 

 fix, the disc by which the larva tixes itself; 

 rnnian numerals I-V, the rudiments of 

 the live arms. 



brl 



further round to the right, and grows in size, the right posterior 

 coelom and the disc covering it become displaced backwards, and 



