I20 THE GENUS MONTICULIPORA. 



seen to be provided with much more numerous and more 

 closely-set tabulae than is the case in the large tubes. All 

 the tabulae are, as a rule, complete, and horizontal or slightly 

 curved ; but 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. 



The species to which this is most nearly allied in its minute 

 structure is M. nodulosa, Nich., and it clearly belongs to the 

 same group of Mo7iticulipo7'CE as M. ramosa, D'Orb. Apart 

 from minor differences, it is distinguished from M. nodtdosa by 

 its stouter form, its want of clearly-marked monticules, and its 

 common possession of opercula to the large corallites. 



Horizon and Locality. — Cincinnati Group, Cincinnati, Ohio. 



Monticulipora tumida, Phillips. 

 (PI. III. figs, i-i/) 



Calaviopora tumida^ Phillips, Geology of Yorkshire, vol ii., PI. I. figs. 49-57, 



1836. 

 Favositcs tiDiiida, Portlock, Geol. Report, p. 326, PI. XXII. fig. 4, 1843. 

 Favosites iumida, M'Coy, Synopsis Carb. Foss. Ireland, p. 193, 1844. 

 Stcnopora tumida, M'Coy, Brit. Pal. Foss., p. 82, 1850. 

 ChcBtetes tin/iidus, Milne- Edwards and Haime, Pol. Foss. des Ter. Pal., p. 



270, 1851 ; and Monograph Brit. Foss. Cor., p. 159, 1852, 

 Monticulipora tumida, De Koninck(?), Nouv. Rech. Anim. Foss. Terr. Carb., 



Pt. I. p. 143, 1872. 

 Cha:tcics tuinidus, R. Etheridge, jun., Ann. Nat. Hist., ser. 4, vol. xiii. p. 194, 



PI. XL figs. 1-3, 1874. 



Spec. Char. — Corallum dendroid, of cylindrical stems vary- 

 ing from two to more than three lines in diameter, which branch 

 dichotomously at irregular intervals. The calices are Irregu- 

 larly polygonal, circular or oval, their apertures being about 

 I -90th Inch in diameter, and their walls being very thick. In 

 well-preserved specimens the walls separating the calices are 

 adorned with numerous blunt spines, and there is also a 

 variable number of minute interstitial apertures intercalated 



