34 



Plate II 



Unless otherwise stated, figures are enlarged thirty diameters. 



Page 



Fig. 1. Hallopora aequalis. Vertical section 19 



Fig. 2. Hallopora aequalis. Tangential section cut from near the surface 19 



Fig. 3. Hallopora maculosa. Tangential section 20 



Fig. 4. Hallopora maculosa. Vertical section, X 10 20 



Fig. 5. Heterotrypa deftnita. Tangential section 21- 



Fig. 6. Heterotrypa definita. Vertical section, X 10 21 



Fig. 7. Heterotrypa robusta. Tangential section 22 



Fig. 8. Heterotrypa robusta. Vertical section, X 10 22 



