PLATE IV. 



Decoeation of Membranes. 

 Fia. 



1. Nitella capillaris. x c. 450. 



2. Nitella capillaris, showing part of the flange with decora- 



tion similar to that of the membrane, x o. 220. 



3. Nitella opaca, showing the scabrous form of membrane. 



X c. 240. 



4. Nitella flexilis, showing the scabrous form of membrane. 



X c. 240. 

 6-9. Nitella spanioclema. 5. — Membrane in the earlier stage 

 of development of protuberances, x c.240. 6. — Later 

 stage showing the granular decoration covering the 

 surface, x c. 420. 7. — A small portion showing the 

 disposition of the granules, x c. 800. 8. — A piece of 

 the flange similarly decorated, x c. 600. 9. — A piece 

 of the inner coloured membrane showing faint 

 granulations, x c. 400. 

 10. Nitella translucens. x c. 375. 



