PHYLUM CHORDATA 



reel txir 

 Tried 



sensi/es 



rect 



slip end adh 

 <#>- "foil. 



fit stiff e-rxcl 





Fig. 201. — Diagram of the metamorphosis of the free, tailed larva into the fixed 

 Ascidian. A, stage of free-swimming larva; B, larva recently fixed: C, older 

 fixed stage, adh, adhesive papillae; atr, atrial cavity; cil.gr, ciliated groove; 

 end, endostyle; ht, heart; mea, ganglion of trunk; n. gu, nerve-ganglion; noto, 

 notochord; or, oral aperture; red, rectum; sens, ves, sense vesicle; st/g, stig- 

 mata; stol, stolon; /, tail. (From Korschelt and Heider, after Seeliger.) 



