122 NORTH AMERICAN INDEX FOSSILS. 



20. C. inclusa Ulrich. (Fig. 178,7.) Ordovicic. 

 Thin incrustations with the oval zocecial apertures occupying, 



each with three mesopores, the bottoms of subtriangular or rhom- 

 boidal obliquely depressed spaces ; lunarium strongly elevated. 



Stones River, Black River, and Tren- 

 ton, of Minnesota. 



21. C. distincta Ulrich. Ordovicic. 

 Apertures oblique, with overhanging 



hood, radially arranged about small 

 maculae and separated by a linear series 



Of mesopores. FIG. 181. Ceramopora imbri- 



Utica and Lorraine Of Cincinnati cata with enlargement of surface. 



region. 



22. C. ohioensis (Nicholson). Ordovicic. 

 Cells in intersecting diagonal lines disposed around elevated 



clusters of larger zocecia ; few mesopores. 



Common in the Utica, Lorraine, and Richmond groups of Ohio, 

 Indiana, Kentucky, Tennessee, Illinois and Wisconsin. 



XVL Crepipora Ulrich. 

 Incrusting, lamellate massive, or hollow branches with long, 

 tubular, thin-walled zocecia, bearing diaphragms, and having an- 

 gular or subpyriform apertures, the lunarium not overarching, its 

 ends usually projecting ; mesopores on elevated or depressed macu- 

 lae. Ordovicic. 



23. C. simulans Ulrich. (Fig. 178, k.) Ordovicic. 

 Clusters of mesopores at intervals of three or four millimeters, 



with the zocecial apertures surrounding concentrically and larger 

 near the clusters ; lunarium not prominent. 



Trenton of Kentucky and Tennessee ; Lorraine of Ohio, In- 

 diana, Kentucky and Tennessee ; Richmond, of Ohio, Indiana, 

 Illinois, Wisconsin and Kentucky. 



XVII. Coeloclema Ulrich. 

 Hollow branches lined internally with striated epithecae; zocecia 

 as in Cetamoporella,b\i\. with thicker walls. Ordovicic. 



24. C. trentonense (Ulrich). (Fig. 178, /.) Ordovicic. 

 Small apertures in depressed areas, with lunarium not promi- 

 nent, and two or three mesopores to each zocecium, regularly or 

 irregularly arranged. 



Trenton of New York, Canada and Minnesota. 



