n8 THE GENUS MONTICULIPORA. 



the Alonticttlipora G Ncalli, James, of the Cincinnati formation. 

 The large coralHtes are, however, on the whole, decidedly 

 larger than In the latter species, while the more minute pro- 

 portions of the corallum and the presence of the well-marked 

 superficial monticules would appear to sufficiently establish Its 

 distinctness, since M. O Nealli Is a decidedly more robust 

 species, and does not appear to be ever furnished with external 

 prominences. 



Horizon and Locality. — Cincinnati Group, Ohio. The speci- 

 mens upon which the preceding description is founded were 

 obligingly furnished to me by Mr U. P. James of Cincinnati. 



Monticulipora (Heterotrypa) O'Nealli, James. 

 (PI. III. figs. yzf). 



Chcetetes? O'Nealli, James, Cat. Foss. Cincinnati Group, 1S75, p. 2. 

 Chcetetes sigi'llarioidcs, Nicholson, Pal. Ohio, vol. ii. p. 203, PI. XXII. figs. 

 9-9^, 1875. 



Spec. Char. — Corallum dendroid, of small dichotomously 

 dividing branches, which vary In diameter from less than a 

 line to about two lines. Surface without monticules, the callces 

 being In general regularly oval, their long axes corresponding 

 with that of the branches, and their long diameter being usu- 

 ally from i-iioth to i-iooth Inch. The larger calices are 

 separated, especially at their upper and lower ends, by a con- 

 siderable number of the minute apertures of a series of inter- 

 stitial tubull. The walls of the larger corallltes are seemingly 

 amalgamated, and are thickened in the outer portion of their 

 course. In the axis of the stems the corallltes are polygonal 

 and remarkably thin-walled, and they bend outwards with an 

 exceptionally gradual Inclination. Complete horizontal tabulae 

 are either absent, or are very sparingly developed In the cen- 

 tral region of the stems ; but similar structures are present 

 in moderate numbers In the outer thickened region of the 

 corallum, and the small Interstitial corallltes are much more 

 closely tabulate than the large tubes. 



