PLATE XXVIII. 



Fig. 1. — A specimen of Stromatoporella curiosa, Barg., of the natural size, 

 forming a crust upon a Rugose Coral. Middle Devonian, Biichel (Paffrath 

 District). 



Fig. 2. — Tangential section of the same, enlarged between 10 and 12 times. 



Fig. 3. — Vertical section of the same, similarly enlarged. 



Fig. 4. — Portion of a polished section of Hermatostroma episcopate, Nich., of 

 the natural size. Middle Devonian (pebble in Triassic conglomerate), Teignmouth. 



Fig. 5. — Tangential section of another specimen of the same, from Shaldon, 

 South Devon, enlarged 10 times. 



Fig. 6. — Vertical section of the preceding specimen, similarly enlarged. 



Fig. 7. — Tangential section of another example of the same, enlarged about 

 15 times. Devonian, Shaldon. 



Fig. 8. — Tangential section of another example of the same, enlarged about 

 15 times. Teignmouth. 



Fig. 9. — Vertical section of the preceding, similarly enlarged. 



Fig. 10. — Portion of a tangential section of Hermatostroma episcopate, Nich., 

 from the Devonian of Shaldon, enlarged rather more than 20 times, showing the 

 porous nature of the skeleton-fibre. 



Fig. 11. — Part of a vertical section of the preceding specimen, similarly 

 enlarged, showing the canal-system infiltrated with some opaque material. 



Fig. 12. — Fragment of Hermatostroma, Schluteri, Nich., of the natural size. 

 Middle Devonian, Hebborn (Paffrath District). 



Fig. 13. — Part of the surface of a concentric lamina of the same, greatly 

 enlarged. 



