3 20 



MANUAL OF ZOOLOGY 

 A 



SECT. 



FIG. 188. 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 ; med. ganglion of trunk ; n.gn. nerve-ganglion ; noto. 

 notochord ; or. oral aperture ; rect. rectum ; sens. i>es. sense vesicle ; stig. 

 stigmata ; stol. stolon ; t. tail. (From Korschelt and Heider, after Seeliger.) 



