PLATE 41. 



Michelixia clappi. Devonian. 



1. Vertical section of a fragment, showing the tabulate septa extrane- 

 ous to the coi'allets' Avails ; from the ferruginous clay of the Mid- 

 dle Devonian, near Louisville. Collection of the author. 

 2. Upper surface of a fragment from the same horizon as example 1, 

 near Louisville. Collection of the author. 



Peocterta (Nov. Gen.) michelinoidea, N. S. Devonian. 



3. 4. Upper surfaces of coralla. 



5. Lateral view of a corallum. 



6. Under surface of a corallum, showing the papillose exothecal secre- 



tion. 



7. 9. Under surfaces of fragments, showing the radiation of corallets 



from the central apex. 



10. Under surface of a corallum, from which a portion of the papillose 



exothecal secretion is removed, so as to show the mural pores 

 perforating the epitheca. 

 12. 13. 14. Views of tube-casts and pore-casts similar to those observed 

 in Pleurodictyum problematicum. 

 All the above examples are from the decomposed hornstone of the 

 Middle Devonian, Falls of the Ohio. Collection of the author. 



8. Under surface of a fragment from the limestone on which rests the 



uppermost chert layer of the Middle Devonian, Falls of the Ohio. 

 Collection of Mr. Gaines. 



11. Under surface of a corallum from which a portion of the exothecal 



layer has been removed, so as to disclose a tube-cast beneath; 

 from the horizon and locality of example 3. Collection of Mr. 

 McConathy. 



Procteria papillosa, Nov. Spec. Devonian. 



15. Upper surface of a corallum, showing papillose exothecal layer sur- 



mounting the corallets' walls. 



16. Under surface of a corallum, showing papillose exothecal secretion 



and the concave margins of the outer walls of the prostrate 

 corallets. 



17. Lateral view of a corallum. 



19. Upper surface of a small corallum with thinner walls than the 

 average. 



18. 20. 21. Under surfaces of coralla. 



All the forms of this species have been found in the decomposed 

 chert of the Middle Devonian, Falls of the Ohio. The examples 

 figured are from the collection of the author. 



