On the Mo)iticuliporoids of the Cinciiuiati Group. 123 



"theoretically" correct idea of Dr. Nicholson, that all the species be 

 grouped under the one genus Monticulipora, with such subdivisions 

 or sub-genera as seem best suited to the exigencies of the case, and 

 which will best enable students and collectors to gain an accurate 

 knowledge of the group. 



There have been recognized of the typical genus Monticulipora 

 as it will here be considered, and as it is represented in the Cincinnati 

 Group, six separate and more or less distinct types. These are 

 as follows, chiefly, if not solely, separated by external characters: 



First. Massive species. In these the corallum is generally at- 

 tached by one point at the base, and is more or less spherical, glo- 

 bose or lobate. 



Second. Discoid species. In these the corallum is a free, more 

 or less plano-convex or concavo-convex disk, with the upper sur. 

 face occupied by calices, and the lower with a striated or wrinkled 

 epitheca. 



Third. Dendroid or Ramose species. In these the corallum is 

 branching, more or less, the stems are cylindrical or sub cylindri- 

 cal, the base free or attached, and the surface of the branches 

 covered with the calices. The extremities of the liranches are 

 rounded. Some are very slender, some more or less swollen, and 

 some few seem to occupy an intermediate place between this and 

 the massive group. 



Fourth. Laminar or Frondescent species. In these the coral- 

 lum is expanded and flattened, generally formed of two lasers of 

 corallites diverging from a central axis. 



Fifth. Encrusting species. In these the corallum forms a crust, 

 growing parasitically on the shells of brachiopods, cephalopods, 

 gasteropods, etc., or on other corals. 



Sixth. Forms taking their shape apparently from the form of 

 the body upon which the corallum has grown, generally very con- 

 stant in each individual species.* 



The surface characters of the species of the genus can be ex- 

 plained in a few words: "Monticules," consisting of a number of 

 cells more or less elevated above the surface of the corallum, and 

 conical or oblong in shape. "Maculag," formed of a cluster of 

 larger or smaller cells on or below the surface; and, lastly in some 

 instances an epithecal membrane, either spread over a portion of 

 the cell bearing surface, or covering the entire under surface as in 

 the species of the Discoid grou]i. In some species it is wrinkled, 



*NichoIson, The Genus Monticu., pp. 34, 36. 



