Pa/eonto/ogy of the Cincinnati Group. 195 



or but slightl}' elevated; apertures wider and the interstitial 

 cells more numerous in the spaces than elsewhere ; apertures 

 oval, 0.2 mm. long and about eight iii the space of 2 mm.; 

 corallites somewhat irregular in their course in the axial 

 region, where the walls are considerably thickened; tabuke 

 complete and horizontal, few in number, but more numerous 

 in the small than in the large cells; spiniform tubuli verj' 

 small. (Geol. Sur. Illinois, vol. 8, i8go, p. 432, as Batosto- 

 mclla simulatrix) 



Locality. — Various points in Ohio and Indiana. Illinois. 



23. — M. COMMUNIS U. P. and J. F. James, 1888. 



Corallum dendroid, but as generall}' found, much broken, 

 the cylindrical or sub-cylindrical stems from one to three 

 lines in diameter, branching at variable distances at acute 

 angles, but masses of considerable size — from one inch to six 

 or eight inches or more in diameter — sometimes found, in 

 which the stems anastomose in a verj" irregular manner ; the 

 surface of most specimens with maculae or monticules, raised 

 little or not at all above the surface, occupied by calices much 

 larger than the average, anfl sometimes clusters of smaller 

 tubules ; calices oval or sub-circular, occasionally somewhat 

 angular ; interstitial corallites numerous, occasionally nearly 

 or quite surrounding the larger cells, and of various shapes ; 

 about six calices in the space of one line in the longitudinal 

 direction of the stem, and seven or eight transversely ; cell 

 walls thin at the surface of unworn specimens, but thickened 

 immediately below ; longitudinal sections show the walls of 

 corallites in the axial region to be thin, becoming thicker at 

 the surface and opening obliquely ; tabulae remote in the 

 axial region, but more numerous near the surface, depressed 

 or bent in the middle or oblique ; the smaller tubes more 

 closely tabulate; transverse sections show corallites to be 

 circular or angular and with cruciform dissepiments; inter- 

 stitial pores variable in shape; in tangential section corallites 

 oval or sub-circular, walls much thickened and " distinctly 

 defined by a dividing space." (Jour. Cin. Soc. Nat. Hist., 

 vol. 10, 1888, p. 175). (yl/. oncallif var. conrmioiis James. 

 The Paleontologist, No. 6, Sept. 12, 1882, p. 47; Callopora 



