Paleontology of the Cinciiniafi Croup. 197 



usually m clusters iu the center of a group of larger-sized 

 corallites; tabulae occurring throughout the corallitcs, incom- 

 plete or complete ; the former in the mature portion of the 

 corallum, the latter in the axial region ; the incomplete 

 tabuke rarely extending more than one-half way across the 

 tube; spiniforni tubuli (?) very small. (Geol. Sur. Illinois, 

 vol. 8, 1890, p. 460, as Batostoma inipcrfcctum) 



Locality. — Wilmington, Ills. 



Remarks — Externally this species is like the previous 

 form, but it is one of those that externally alike is internally 

 different, this difference consisting principally in the imper- 

 fect tabulae. 



25. — M. jAMESi Nicholson, 1874. 



Corallum dendroid, branching irregularly or dichotomously, 

 sometimes terminating in rounded ends, branches varying 

 from two to five lines in diameter ; surface smooth or nearl}' 

 so; calices oval or rounded, sometimes indented on one or 

 more sides, thick-walled, surrounded by a ring-like wall ; 

 intercellular spaces solid, or with a variable number of small 

 tubes, or with blunt spines, apparently the solid apices of the 

 interstitial cells; large corallites angular, polygonal and thin- 

 walled in the center of the branches; becoming thickened as 

 they approach the surface, each one in the outer portion of 

 the branches surrounded by a distinct, ring-like wall; small 

 interstitial corallites variable in size and shape, occupying the 

 entire interval between the large ones; numerous spiniform 

 tubuli also developed ; tabulae wanting or very sparsely devel- 

 oped in the axes of the branches; remote in the larger 

 corallites but numerous and closely set in the smaller ones, 

 always complete and horizontal or slightly bent. (Quart. 

 Jour. Geol. Soc. Lond., vol. 30, 1874, p. ^o6,2isChcstetes jainesi ; 

 Genus Montic, 1881, p. 143.) {M. implicata (Ulrich) Nichol- 

 son, Genus Montic, 1881, p. 147.) 



Locality. — Cincinnati, Ohio. 



Remarks. — The peculiarly -indented walls and the rings 

 surrounding the apertures are marks of this species. M. 

 im-plicata does not seem to differ in any essential characters, 

 and it is therefore regarded as a synonym. Its main features 

 are given below : 



