On the Montic2iliporoid Corals of the Cincinnati Group. 25 



to foreign bodies, generally the shells of brachiopods [Strophomena 

 alternata, etc.) More or less convex above. Surface generally 

 smooth, but often with a single central elevation. Calices sub- 

 circular, mostly equal, with moderately thick walls. No interstitial 

 cells. 



Obs. — This is a peculiar little species, which can scarcely be 

 mistaken for any other. It is questionable whether it may not be 

 the base of some other species; possibly the young corallum of 

 some encrusting form like M. papillata. Nicholson, indeed, makes 

 such a suggestion, but does not think it likely. He says, further, 

 that "at any rate, in the absence of any specimen by which this 

 could be directly connected with any other known form, I have 

 thought it best to place it under a separate title, since it is not only 

 common in its occurrence, but is also very constant in its size and 

 other characters."* 



Formation and Locality.— Lower Silurian, Trenton Group, 

 Kentucky and Minnesota; Cincinnati Group, at Cincinnati, O. 



48. M. DYCHEi, U. P. James. 



Moniiculipora [Monotrypa) dychei, James. The Palseont. , 52, 

 1882. 



M. dychci, James, Jour. Cin. S. Nat. ftist., VI, 235, 1883. 



Corallum sub-fusiform in outline, parasitic on a crinoid col- 

 umn, with rough, nodular swellings, low ridges and annular con- 

 strictions. Surface with slightly raised, rounded monticules, irreg- 

 ularly distributed over the surface, and occupied by calices slightly 

 larger than the average. Calices polygonal; walls of cells thin 

 and sharp; interstitial tubes wanting. 



Obs. This species is one easily recognized by the peculiar 

 form, and its place of growth. The crinoid stem upon which the 

 corallum grows is easily seen at either end. Tne type specimen is 

 seven inches long, and tapers both ways from a diameter of two 

 inches to but little more than the size of the crinoid stem. 



Formation and Locality. Lower Silurian, Cincinnati Group, 

 Upper beds at Cincinnati and Lebanon, O. 



49. M. CLAVACOIDEA, U. P Jamcs. 



Monticidipora {Monotrypa) davacoidea, James. Nicholson, 

 Genus Montic, 182, 1881. 



Chatctcs davacoideiis, James. Cat. Low. SI. Foss. Cin. Gr. 



*i'.al Oh o, 1 . 213. 



