2 26 THE GENUS AIONTICULIPORA. 



say, the tabulae are twofold, those on one side of the tube 

 forming a longitudinal series of lenticular vesicles, while those 

 on the other side run from these vesicles to the opposite wall, 

 and are either straight or slightly concave. Occasionally, one 

 of the large corallites shows only complete tabulee, but this 

 is probably due to its being intersected on one side. 



Good observers regard this as the real type of the M. 

 mammulata of D'Orbigny ; and its superficial characters, un- 

 doubtedly, would justify such a reference, as they agree very 

 well with the description given by Milne-Edwards and Haime. 

 For reasons previously stated, however, superficial characters 

 alone will not settle this point, and I have preferred to regard 

 another externally similar species as the type of M. mamniiL- 

 lata; though I quite admit that the present form might be 

 selected in its place with perfect propriety. From the form 

 which I have called JM. mammulata, D'Orb., the present species 

 is entirely separated by its minute structure, and, especially, by 

 the smaller number of the interstitial corallites, the absence of 

 *' spiniform corallites," the greater thinness of the walls, and the 

 presence of incomplete tabulae In the large corallites. 



Horizon and Locality. — Common in the Cincinnati Group, 

 Cincinnati, Ohio. 



Monticulipora (Peronopora) Cincinnatiensis, James. 



(PI. II. figs. 6-6r.) 



Chatetes Cincinnatiensis, James, Cat. Sil. Foss., 1S75, P- 2. 



Spec. Char. — Corallum encrusting, forming a layer of a line 

 or less in thickness, attached by the whole of the under surface 

 to foreign objects. External surface covered with numerous 

 bluntly conical and very prominent monticules, the bases of 

 which are close together. Calices sub-polygonal, thick-walled, 

 with a moderate number of Interstitial tubes in the intervals 

 between them. Corallites of two kinds, the larger ones grener- 

 ally oval or circular, about i-goth inch in diameter, the smaller 



