PLATE XIX. 



Fig. 1. — Clathrodicti/on fastigiatum, Nich., a small specimen from the Wenlock 

 Limestone of Ironbridge, showing the upper surface, of the natural size. (Page 

 152.) 



Fig. 2. — Under surface of the same, showing the wrinkled epitheca. 



Fig. 3. — Surface of a specimen of the same from the Wenlock Limestone of 

 Dudley, of the natural size. 



Fig. 4. — Tangential section of a specimen of the same from the Wenlock 

 Limestone of Ironbridge, enlarged 10 — 12 times. 



Fig. 5. — Vertical section of the preceding, enlarged 10 — 12 times. 



Fig. 6. — A specimen of Clathrodictyon striatellum, D'Orb. sp., from the 

 Wenlock Limestone of Dudley, showing the upper surface, of the natural size. 

 (Page 156.) 



Fig. 7. — Portion of the weathered surface of another specimen of the same from 

 Dudley, showing zotiidal pores, enlarged. 



Fig. 8. Vertical section of a specimen of the same, from the Wenlock Lime- 

 stone of Ironbridge, enlarged 10 — 12 times. The vertical sections of this species 

 figured in Part 1 of this Monograph (Plate I, fig. 1, and Plate V, fig. 3) have been 

 inadvertently reversed in position, and their lower margin should properly be 

 placed uppermost. 



Fig. 9. — Tangential section of the preceding specimen, enlarged 10 — 12 times. 

 Part of the section corresponds with an interlaminar space, and part corresponds 

 with one of the concentric laminse. 



Fig. 10. — Part of the surface of a silicified specimen of Siromatopora mammillata, 

 Fr. Schmidt, from the " Borkholm'sche Schichten " of Esthonia, enlarged 3 times. 

 From a specimen presented to the author by Magister Schmidt. (Page 158.) 



Fig. 11. — Vertical section of the preceding specimen, enlarged about 14 times. 



Fig. 12. — Tangential section of the same, enlarged 14 times. The appearance 

 of a dark centre to the radial pillars is the result of silicification. 



