xm PHYLUM CHORDATA 125 



blastopore becomes the anus, there being no proctodseum. The 





f iisi-frf 



C:lSil&*M 





p*lf "*.. 



g'o'w^ *5? -. 



lumen of the intestine is semilunar, owing to the presence of a 

 typUosole (Fig. 811, int.), which takes a somewhat spiral course 



