Paleontology of the Cincinnati Group. 203 



Remarks. — This is another one of the species found in 

 rocks of the Cincinnati Group in Illinois, which has so far 

 not been recorded from our region. The peculiarly-arranged 

 and conspicuous maculae form a readily distinguishing mark, 

 and this feature, in connection with the peculiar tabulation of 

 the corallites, would seem to make the species easily recog- 

 nizable. 



32. — M. SEPTOSA Ulrich, 1879. 



Corallum ramose ; branches cylindrical or sub-cylindrical ; 

 surface with broad, low monticules, about one line apart and 

 occupied by groups of cells larger than the average ; calices 

 polygonal, rather regularly arranged ; walls of corallites thin ; 

 no interstitial corallites; worn specimens show peculiar pro- 

 jections from the cell walls into the cell cavity ; longitudinal 

 sections show the corallites to be nearly vertical in the center 

 of the branch, where they have very thin walls and are 

 crossed by very thin and remote tabulae; they then bend out- 

 ward, and as the surface is reached the walls are thicker and 

 the tabulae more numerous; pseudo-septa are conspicuous in 

 tangential sections, three or four in each corallite. (Jour. 

 Cin. Soc. Nat. Hist., vol. 2, p. 125, as Atactopora scpiosa ; Ibid., 

 vol.^5, 1882, p. 255, as Arnplexopora scptosa.) 



Locality. — Cincinnati, Ohio. 



33. — M. KENTUCKENSiS James, 1883. 



Corallum dendroid; branches cylindrical; about one line, 

 more or less, in diameter, branching dichotomously or anas- 

 tomosing ; surface with low monticules irregularly dis- 

 tributed ; calices polygonal, of various forms and sizes; walls 

 comparatively thick at apertures; no interstitial pores; longi- 

 tudinal sections show corallites in the center of the branch 

 diverging slightly from a longitudinal direction, the inclina- 

 tion increasing toward the surface, some corallites opening 

 obliquely, some at right angles to their course; in some cases 

 the walls bifurcate, forming tubes with pointed bases and 

 with apertures of the normal size; walls comparatively thick 

 throughout; tabuke numerous in all parts of the corallites ; 



