XIII 



PHYLUM CHORDATA 



33 



and by the tail aborts, and two processes, one postero-dorsal. the 

 other ventral, known respectively as the dorsal (dors, st.) and ventral 



reel 



C stol 



end 



FIG. 691. Diagram of the metamorphosis of the freetailed 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 ; ctl. a,: ciliated groove ; end. endostyle ; lit. heart ; mcd. ganglion of trunk ; 

 71. gn. nerve-ganglion ; noto. notochord ; or. oral aperture ; net. rectum ; sens. res. sense 

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



stolons (vent, st.), grow out from the body of the larva. On the 

 latter are formed a number of slight projections or buds. These 



VOL. II 



D 



