PLATE CX. 



POLYSTOMELLA. 



a, Lateral aspect ; b, peripheral aspect. 



Diam Page 



Figure 1. — Polystomella subnodosa, Miinster, sp., . x 75 734 



,, 2-5. — Polystomella arctica, Parker and Jones, . . . 735 



Figs. 2a, 3, Lateral aspect; fig. 2 b, peripheral 



aspect, .... x 30 



Fig. 4. Horizontal section, showing the seg- 

 mentation, and the laminated thicken- 

 ing of the walls, . . . x 30 



Fig. 5. Portion of a section, more highly 

 magnified, showing tlie septal aper- 

 tures, and the forked interseptal 

 canals the openings of which form 

 the double rows of sutural orifices, . x 100 



,, 6, 7. — Polystomella crispa, Linne, sp., . . x 40 736 



,, 8, 9, 11. — Polystomella macella, Fiehtel and Moll, 



sp., ..... x 45-GO 737 



„ 10. — Young specimen, possibly of the same 



species, with the peripheral ends of 

 the septa forming angular or pointed 

 projections, . . . x 



12. — Polystomella verriculata, Brady, . x 



13-15. — Polystomella imperatrix, Brady, . x 



16-17. — Polystomella eraticulata, Fiehtel and 



Moll, sp., .... x 30-40 739 



