On the Moiticuliporoid Corals of the Cincinnati Group. 2 1 



42. — M. TUBERCULAIA, EdvV. & H. 



Monticulipora {Afonotrypa) tiibenidata, Edvv. & H. Nicholson, 

 Genus Montic, 200, 1881. 



Cheetetes tuberculatus, Ed. &. H. Pol. Foss. des Terr. Pal., 

 268, 1851; Nicholson, Ann. Nat. Hist. ser. 4, XVIII, 91, 1876. 



ChcEtctcs corticans, Nicholson, Quart. Jour. Geol. Soc, XXX, 

 512, 1874: Pal. Ohio II, 210, 1875. 



Atactopora hirsuta, Ulrich, Jour. Cin S Nat. Hist. II, 120, 

 1879; VI, 245, 1883. 



A. maculata, Ulrich. Ibid, II, 121, 1879; VI, 246, 1883. 



Spatiopoi-a tuberculata, Ulrich. Ibid, VI, 166, 1883. 



.S'. montifcra, Ul. Ibid, VI^ t68, 1883. 



Corallum parasitic, forming a more or less extensive crust, 

 from one-fourth of a line to two lines thick, ordinarily about one- 

 half a line, attached to the outer surfaces of shells of Orthoceras 

 and Endoccras. Surface with a number of long and narrow or 

 rounded monticules, arranged with more or less regularity in diag- 

 onal lines, and with their longer diameter in the same direction as 

 the long axis of the shell upon which they grow ; summits generally 

 compact. Calices small, polygonal, nearly equal in size, with 

 occasionally a few interstitial corallites. Walls of calices rather 

 thick at the surface, thinner beneath, sometimes bearing on their 

 margins one or two rows of minute tubercles. 



Obs. — As shown by the synonomy, this species has been de- 

 scribed under various names. Atactopora hirsuta and A. maculata 

 are names given to two forms, one bearing two rows of spines and 

 the other a few only on the edges of the calices ; they also have 

 rather rounded monticules. In speaking of the figures of these two 

 species, their author says: "Comparing figure 2 with figure i, both 

 representing tangential sections, . . . we find that with the 

 exception of the relative thickness of the cell interspaces or walls, 

 the two species are precisely alike. In both we find the same 

 peculiarly constructed ' maculae,' while in the minute structure of 

 the cell walls, no difference whatever is apparent. In their vertical 

 sections a corresponding agreement of structure is apparent."" The 

 species is mainly recognized by the well developed, elongated 

 monticules. 



Formation and Locality. — Lower Silurian, Cincinnati Group, 

 from the lowest rocks at Cincinnati to the highest beds in Warren, 

 Clinton and Butler Counties, O. 



*,Iour. Cin. S. N. H. VI, 246. 



