90 Morris and Raff: Asynimetron bassanum. 



Plate XX. 



Fig. 10 — Diagrammatic transverse section behind atriopore 



showing right and left atrial caecae as in Fig. 3. 

 ,, 11 — Anterior end showing incomplete ring of pigment 



around anterior end of notochord. 

 „ 12 — Drawing compiled from a series of transverse sections 



through the pigment ring. 

 ,, 13 — Transverse section through oral hood showing 



pigment in spaces 



