PLATE XL. 



Figures magnified 375 diameters. 



PAGE. 

 Fig. 1. MICRASTERIAS FIMBRIATA, semi-cell, typical form, . . 121 



" 2. other semi-cell, Var. apiculata, . 121 



" 3. " ' one-fourth cell, Var. Elephantina, . 121 



" 4. " " Var. nuda, . , . 121 



Figs. 5, 0. two varieties of polar lobes, . .121 



Fig, 7. MICRASTERIAS SUBFIMBRIATA, has the form of lobelets, but not 



the specific number, . . 121 

 " 8. MICRASTERIAS SIMPLEX, unlike all other forms in the simple, 



acute, ultimate division of the lobules, 121 



