PLATE V. 



Fig. 1. A specimen of Monticulipora {Hdcrotrypa) Audrcivsii, Nich., from the 



Cincinnati group of Ohio, of the natural size. 

 Fig. I a. Part of the surface of the same, embracing one of the clusters of large 



tubes, enlarged twenty-five times. 

 Fig. 2. A specimen oi Monticulipora {Heterotrypa) siibpidchella, Nich., from the 



Cincinnati group of Ohio, of the natural size. 

 Fig. 2 a. Part of the surface of the same, including one of the clusters of small 



tubes, enlarged twenty-five times. 

 Fig. 3. Outline of a specimen oi Monticulipora {Heterotrypa) Daivsoni, Nich., of 



the natural size. From the Cincinnati group of Ohio. 

 Fig. 3 a. Part of the surface of the same, of the natural size, showing the 



prominent elongated tubercles. 

 Fig. 3 h. Part of the surface of the same, enlarged eighteen times. 

 Fig. 3 c Tangential section of the same, enlarged eighteen times. 

 Fig. 3 d. Part of the preceding section, enlarged fifty times. 

 Y\g. 3 e. Vertical section of the same, embracing the whole thickness of the 



corallum, enlarged eight times. 

 Fig. 3/ Part of the outer margin of the preceding section, enlarged eighteen 



times. 

 Fig. 4. A thin variety of Monticulipora {Peronopora) fronJosa, D'Orlx, from the 



Cincinnati group of Ohio, of the natural size. 

 Fig. 4 a. Tangential section of the same, enlarged fifty times, showing the 



imperfect tabular of the larger corallites, the intercalated small corallites, 



and the moderate development of " spiniform corallites." 

 Fig. 5. A fragment of Monticulipora {Peronopora) frondosa, D'Orb., from the 



Cincinnati group of Ohio, of the natural size, showing the faintly marked 



monticules. 

 Fig. 5 a. Broken edge of the same specimen, of the natural size, showing the 



general arrangement of tlie corallites. 



