I7<S Cincinnali Society of Natural History. 



MANUAL OF THE PALEONTOLOGY OF THE CIN- 

 CINNATI GROUP. 



By Joseph F. James, M. Sc, F. G. S. A., etc. 



Part V. 



(Continued from Vol. XV, p. 159.) 



Group II. Discoid : Free, plano-convex, concavo-convex, 

 or conical ; upper surface bearing apertures, the lower cov- 

 ered with an epitheca. 



a. Corallum concavo-convex. 



epitheca concentrically wrinkled. 



t calices generally similar 5 



tt clusters of larger calices. 



+ calices polygonal 6, 7 



XX calices circular or sub-circular 8, 9 



* epitheca with radiating striae; calices circular, 10, 11 



* epitheca with striiu extending from a point at 



one side 12 



* epitheca with a groove 13 



b. Corallum conical. 



* edges thin. 



t epitheca with a grove 13 



tt epitheca concentrically wrinkled. 



X monticules small M. '5 



++ monticules prominent 16 



5. — M. DiscoiDEA (James) Nicholson, 1871. 



Corallum free, discoid, concavo, or plano-covex, sharp- 

 edged, from five to eight lines in diameter, and about one 

 line in thickness in the center; under surface generally con- 

 cave, covered with a thin, smooth and irregularly striated 

 epitheca, usually with two or three marked, concentric 



