Paleontology of the Cincinnati Group. 189 



larger corallites to have horizontal and complete tabulae and 

 also a series of incomplete tabulae forming a series of vesicles 

 along one side of the tube ; small corallites with numeroiis 

 complete and horizontal tabukc. (Cat. Low. Sil. Fossils, 

 1875, p. 2, as Clurlctcs cincinnatiensis ; Nicholson, Genus 

 Montic, 1881, p. 226). {M. consimilis Ulrich, Jour. Cin. Soc. 

 Nat. Hist., vol. 5, Dec, 1882, p. 238. Prasopora nodosa 

 Ulrich. Ibid, p. 245). 



Locality. — Cincinnati and Oxford, O.; also, Trenton group 

 at Nashville, Tenn. 



Remarks. — This is a well-marked species, especially dis- 

 tinguished by the prominent, conical monticules. Of the two 

 species placed as synonyms only a single fragment was found 

 of the first ; and although the second was from a lower 

 horizon (upper Trenton, of Tennessee), there does not seem 

 any reason for separating it as a distinct species. The two 

 species are described below for comparison. 



M. consimilis. Corallum attached to shell of a Strophomena, 

 the upper surface with unequally distributed, compres.sed 

 and prominent monticules, the summits occupied by apertures 

 of small cells and the slopes by cells larger than the average ; 

 ordinary cells thin-walled, polygonal, y^-o to j\-^ inch in 

 diameter ; longitudinal sections show in the immature portion, 

 thin-walled cells, crossed by straight or oblique tabulae, with 

 a few vesicles in the larger cells ; in the mature portions the 

 walls are thicker, and both straight tabulae and vesicles are 

 more numerous ; transverse sections show polygonal and 

 thin-walled cells, the visceral chamber being crossed by 

 delicate laminae excavated on one side in a crescentric or 

 triangular manner, exactly as in cincinnatiensis. 



Prasopora nodosa Ulrich. Corallum small, irregular or 

 hemispherical, one to one and one-half inches in diameter; 

 lower surface lined with a wrinkled epitheca ; upper convex, 

 covered by prominent, closely-arranged but usually unequal 

 monticules; calices sub-circular, walls thin, varying from 

 tIu to y|^ inch in diameter ; angular, interstitial cells fre- 

 quently present; internally made up of two kinds of coral- 

 lites, the larger with thin, di-stinct w^alls, oval or sub-circular, 

 J- .}^ inch in diameter and only in contact at certain points; 

 tabulae straight and forming vesicles along one side of the 



