ANTHOZOA—TABULATA. 89 



Common in the Onondaga and Hamilton beds of New York. 

 Canada, Michigan, and the Falls of the Ohio region. 



98. F. limitaris Rom. (Fig. 142.) Devonic. 

 Cylindrical, commonly branching stems 5 to 15 mm. in diam- 

 eter. Calices circular, opening at nearly right angles to the axis 

 of the branch. Walls thick, the division lines between the coral- 

 lites shown only in certain states of preservation. 



Common in the Onondaga limestones of the Falls of the Ohio. 

 Also in the Onondaga and Hamilton of New York, Canada, 

 Michigan, etc. 



XXXVI. Pleurodictyum Goldfuss. 

 Corallum depressed, discoidal, lower surface covered by a con- 

 centrically wrinkled peritheca. Corallites small, prismatic, funnel- 

 shaped ; septa faint or obsolete, a scanty development of tabulae 

 occurring; mural pores irregularly distributed. Young cells as in 

 Aulopora. Devonic. 



99. P. stylopora (Eaton). (Fig. 143.) Devonic. 

 Heads from I to 2 inches in diameter, septa faint, forming a 



crenulation on the calyx margin ; tabulae moderately numerous. 



Common in the Hamilton beds of New York 

 and Michigan. 



Fig. 143. Pleuro 

 dictyutn stylopora. 



XXXVII. Michelinia De Koninck. 

 Convex or hemispheric heads consisting of 

 prismatic corallites and basally covered with 

 a wrinkled peritheca. Septa represented 

 by longitudinal ridges. Tabulae numerous, crowded and convex 

 upward, often incomplete and uniting. Mural pores numerous, 

 irregularly scattered. Differs from Favosites in the greater diam- 

 eter of the corallites, in the crowded arched tabulae and in the 

 numerous irregularly scattered mural pores. Dev.-Carb. 



100. M. convexa (d'Orbigny). (Fig. 144.) Devonic. 

 Calices 8 to 10 mm. in diameter. Tabulae thin, very close, 



strongly arched in the center, vesicular at the base. 



In the Onondaga limestone of Canada, Michigan and the Falls 

 of the Ohio region. 



101. M. cylindrica (Michelin). Devonic. 

 Corallites subcylindrical ; on the interior are regular annulations 



