XVII 



PEOTOCHORDATA 



601 



the myotomes, and which project into spaces derived from the posterior 

 lower angles of the myocoeles, as the cavities of the myotomes are 



called. These spaces form the gonocoeles of the adult ; they soon 

 become cut off from the myocoeles from which they are derived by 

 the growth of septa, and each gonad projects into the gonocoele 

 derived from the myocoele in front of the one to which it belongs. 



