20. CONTRIBUTION, TO 



The small spines at the margin of the cups, and smooth convex tabulae, 

 makes this easily recognized from all other species. 



Found in tlie middle Devonian (upper Helderberg group) at the Falls of 

 the Ohio. Now in the collection of the author. 



MICHELINIA PAPULOSA, N. Sp. 



Plate 7, Figs. 13-14-15. 



Corallura, composite, small, not exceeding ten millimeters in its greatest 

 diameter, three millimeters in thickness. Tubes rounded, unequal in size, two 

 millimeters in diameter, with very thick walls, space between the margins one- 

 fourth the diameter of the tubes, slightly elevated above the margin of the 

 cups, finely notched, giving to the cup a fine crenulated appearance, lineal fur- 

 rows fine, distinct, especially near the margin of the tubes. Mural pores small, 

 rather few in number compared to other forms of Michelinia, dispersed with- 

 out system; surface of corallum convex. With a concave base, covered with fine 

 papulose secretion. 



Found in the middle Devonian (upper Helderberg group) at the Falls of 

 the Ohio Now in the collection of the author. 



MICHELINIA N E G L E C T A, N. Sp. 



Plate 7, Fig. 16. 



Corallum small, not exceeding five millimeters in its greatest diame- 

 ter, slightly less than two millimeters in thickness, tubes polygonal, un- 

 equal in size, two millimeters or less in diameter; lineal furrows, fine, dis- 

 tinct. Tube walls thin. Mural pores numerous and irregularly dispersed. Tabu- 

 he smooth, slightly oval; surface of corallum convex, with a slightly concave 

 base covered with a fine granulose structure. 



The thin walls, and numerous mural pores, and the unequal polygonal tubes, 

 makes this easily recognized from all other species. 



Found in the middle Devonian (upper Helderberg group) at the Falls of 

 the Ohio. Now in the collection of the author. 



MICHELINIA LOUISVILLENSIS, N. Sp. 



Plate 8, Figs. 10-11-12. 



Corallum small, thin, not exceeding ten millimeters in its greatest 

 thickness, with a stout wrinkled epithecal crust on the under side. 

 Acute at the point of attachment, diameter varying in different individuals 

 from eight to twenty millimeters, the broadest examples observed. Tubes 



