532 



OLWEN M. REES. 



,U 



Fig. 8. — S. sphyrodda. Section through 

 the trilobed mesenterial filament. 



locLy Wo.ll. 



Fig. 7. — S. sphyrodeta. Transverse section 

 through a young specimen in a fully ex- 

 panded condition, showing one of the 

 perfect mesenteries. 



