78 Cincinnati Society of Natural History. 



Group V. Incrusting or parasitic : Forming patches or crusts 

 of greater or less extent and growing on various species of shells or 



corals. 



a. Corallum forming a thin crust. 



* Surface with elongated monticules 61 



* Surface with rounded or conical monticules. 62, 63, 64, 65 



* Surface smooth: 



y With groups of cells larger than average 66, 67 



f Without groups of larger cells 68 



b. Corallum forming irregular masses about crinoid columns. . 69 



c. Corallum fusiform or clavate 70, 71 



d. Corallum sub-globular or irregular 72 



e. Corallum forming well-defined, generally small patches. 73, 74 



f. Corallum hemispheric or conical 75, 76 



6l. M. TUBERCULATA Edw. & H. (sp.), 1 85 I. 



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 Endoceras ; 

 surface with a number of long and narrow or rounded monticules, 

 arranged with more or less regularity in diagonal 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 tuber- 

 cles; tabula? when developed, complete. (Pol. Foss. des Terr. Pal., 

 1 85 1, p. 268, as C/uvtetes: Nicholson, Genus Montic, 1881, p. 200.) 

 (Chcetetes corticans Nicholson, Quart. Jour. Geol. Soc. Lond. , vol. 30, 

 1874, p. 512; Atactapora hirsuia Ulrich, Jour. Cin. Soc. Nat. Hist., 

 vol. 2, 1879, p. 120: Ibid., vol. 6, 1883, p. 245 : A. metadata Ulrich, 

 Ibid., vol. 2, 1879, p. 121: vol. 6, 1883, p 246; Spaiiopora montife?-a 

 Ulrich, Ibid., vol. 6, 1883, p. 168.) 



Locality. — Cincinnati and various places in Warren, Butler and 

 Clinton counties, Ohio. 



Remarks. — The differences which are relied upon by Mr. Ulrich 

 to separate Atactapora hirsuta and A. viaadata from the present species 

 we do not believe to be sufficient to justify such separation. The same 



