172 Cincinnati Society of Natural History. 



II. Surface with maculee or low monticules. 

 a. calices polygonal or sub-polygonal. 



^[clusters of cells larger than average ; interstitial 

 cells few 25 



* clusters of cells smaller than average; interstitial 



walls numerous 26 



* low monticules present; no iniersiiiial cells. . , 27, 28 

 b. calices oval or circular. 



* maculae or monticles formed of smaller cells. .29 



III. Surface with conspicuous monticules. 



a. calices of two kinds ; monticules elongated or conical. 



* calices large, sub-polygonal 30 



* calices large, oval 31 



* calices ovate or sub-circular 32 



b. calices of two kinds; monticules conspicuous, arranged 



in alternate manner 33 



c. calices sub-equal ; monticules small, arranged in altern- 



ate manner , ... 34 



15. M. BRiAREA, Nicholson. 



Monticulipora {Monotrypa) briarea, Nich. Genus Montic, 198, 

 1881. 



Chcetefcs briareiis, Nich., Pal. Ohio, II., 202, 1875. 



Monotrypella briareus, Ulrich. Jour. Cin. S. Nat. H., V., 248, 

 256, 1882. 



Corallum free, dendroid, expanding above ; branches variable 

 in number, two and one-half to four lines in diameter, cylindrical, 

 possibly branching more than once. Surface smooth. Calices of 

 one kind only, oval or circular. Walls of corallites thick at the 

 surface. Interstitial tubes and spiniform corallites wanting. 



Obs. This is quite a peculiar species, with an apparently free 

 base, tapering to a point and branching in a digitate manner above. 

 One of us has a very large specimen on a slab, some six inches 

 long and spreading out two inches or more at the top. The ordinary 

 specimens, however, are from one and a half to two inches long. 

 The free, pointed base will serve to readily distinguish it from the 

 other dendroid species. 



Formation and Locality: Lower Silurian, Cincinnati Group, 

 Cincinnati, O. Hudson River Gr., Wisconsin. 



