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 



p.da.. 



FIG. 362. Lateral views of the brachio- 

 larian phase of the larva, of Asterias 

 inilgaris in various stages of fixation 

 and metamorphosis. (After Goto. ) 



A, earliest stage: temporary fixation by 

 means of the brachiolarian arms : prae-oral 

 lobe undiminished. B, later stage : permanent 

 fixation 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. 360. In addition, 

 fix, the disc by which the larva fixes itself ; 

 roman numerals I-V, the rudiments of 

 the five arms. 



brl 



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

 coelorn and the disc covering it become displaced backwards, and 



