PLATE XIV 



Fig. i. A typical individual of Rhizosolenia curvata. 



Figs. 2-4. Outlines indicating the normal limits of size variation. 



Fig. 5. Vegetative division, an early stage. 



Fig. 6. Vegetative division, advanced stage. 



Fig. 7. An auxospore of RJiizosolenia curvata. 



Fig. 8. Frustules in catena. 



Fig. 9. "Rafting" of individuals of different diameters. 



