194 Citicinuati Society of Natural History. 



Remarks. — The species is described as occurring in Illinois 

 in beds of the same age as those at Cincinnati, and it is 

 inserted here on that account. It presents many features of 

 resemblance to both the preceding and the following species, 

 but in the present state of knowledge it is considered best to 

 regard it as distinct. 



2 1. — M. o'nealli James, 1875. 



Corallum dendroid, branching dichotomously, branches vary- 

 ing from less than one line to two lines in diameter; surface 

 smooth, calices generally oval, long axes corresponding to the 

 long axes of the branches ; of two kinds, the larger separated 

 by a considerable number of interstitial tubes ; walls thick- 

 ened at cell mouths ; operculae often closing apertures of 

 cells ; corallites in the axial region polygonal and thin-walled, 

 bending outward with an exceptionally gradual inclination ; 

 complete, horizontal tabuke either absent or veiy sparingly 

 developed in the central region, but present in moderate 

 numbers in the outer thickened-walled region ; small inter- 

 stitial corallites more closely tabulate than the large ones ; 

 "in some cases a few of the tabulae in the throat of the large 

 tubes may become so bent as to unite with one another, and 

 to form a small number of lenticular vesicles in this region." 

 (Nicholson, Genus Montic, p. 120.) (Cat. Foss. Cin. Group, 

 1875, p. 2, as C/iatetes? o'nealli.) {C/icstetes sigillaroides, 

 Nicholson. Pal. of Ohio, vol. 2, 1875, p. 203; Genus Montic, 

 1881, p. 120.) 



Locality. — Cincinnati, Ohio. 



Remarks. — This species has a peculiar habit of growth, 

 branching at almost every possible angle, and anastomosing 

 so as to form various figures. It also has a considerable 

 number of interstitial corallites among the normal ones. 

 Chwtetes sigillaroides is undoubtedly a .synonym, although it 

 is retained as a species by some authors. 



22. — M. siMUL.VTKix llrich (sp.), 1890. 



Corallum dendroid, with cylindrical branches 2 to 3 mm. 

 in diameter; surface smooth, with clusters of cells not at all 



