SYNURA.-A PLANT INJURIOUS TO DRINKING WATER. 

 Fig. I. — Elongated colouy. 

 Fig. 2. — Spherical colouy — ordiuary form. 

 Fig. 3. — Encysted state. 



Fig. 4. — Disintegrating zooids — oil globules escaping. 

 Fig. 5. — Zooids flattened under the cover-glass, showing 



oil-globules. 

 Fig. 6. — Zooids flattened under the cover-glass — a variety 



with crenulated margin. Not common. 



