COEALS OF THE CINCINNATI GROUP. 213 



the possession of very well-marked and conspicuous groups of large sized 

 corallites. It differs from this latter species, however,, in its never pos- 

 sessing minute interstitial tubuli, so far as I have seen, and in the ap- 

 parently very large size of the calices produced by the extraordinary 

 thinness of the walls. From such free forms as G. petropolitanus and C 

 discoideus, it is distinguished by its extreme thinness as compared with 

 its breadth, as well as by the large size of the corallites. 



The above description is drawn from specimens obligingly furnished 

 me by Mr. U. P. James, and I have named the species in honor of Pro- 

 fessor Newberry, one of the most distinguished of palteontological ob- 

 sei-vers and writers. 



Locality and position : Cincinnati group, Cincinnati, Ohio. 



CHiETETES PETECHIALIS, Nicholson. 

 Plate 22, figs. 5, 5a. 

 Corallum incrusting, forming small circular patches, from less than 

 half a line to a line and a half in diameter, attached by their bases para, 

 sitically to some foreign body, and more or less strongly convex above. 

 The surface is usually smooth, but not uncommonly exhibits a single 

 central elevation or tubercle. The calices are sub-circular and sub-equal, 

 with moderately thick walls, their margins not tuberculated or granu- 

 lated, entirely without minute interstitial tubuli, their size very small, 

 from fourteen to sixteen occupying the space of one line. The corallites 

 in the center of the mass are nearly perpendicular, but they become 

 more or less oblique toward the margins. 



It is possible that this may be a young form of some other incrusting 

 species, such as C. papillatus, McCoy j but I do not think this is the case. 

 At any rate, in the absence of any specimens by which this could be 

 connected directly 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 oc- 

 currence, but is also very constant in its size and other characters. It 

 is distinguished by its forming very minute, circular, and convex 

 patches, by the absence of interstitial tubules, and by the extremely 

 small size jf the calices. All the examples which I have seen are at- 

 tached parasitically to the exterior of Strophomena alternata and different 

 species of Chastetes, and in general many colonies are found attached to 

 the same object. I am indebted for the specimens from which the above 

 description is drawn to the kindness of Mr. U. P. James. 



Position and locality : Cincinnati group, Cincinnati, Ohio. 



