208 PALEONTOLOGY OF OHIO. 



and do not, therefore, exhibit the sub-massive mode of growth which is 

 stated to be characteristic of this species. 



Position and locality : Cincinnati group, near Cincinnati, Ohio. From the collection 

 of Mr. XJ. P. James. 



Chjetetes frondosus, D'Orbign}^? 



Plate 22, figs. 1, 15. 



MonticuUpora frondosa, D'Orbigny; Prodr. de Paleontologie, 1850. 



Chxtetes frondosus, Edwards and Haime; Pol. Foss. des Terr. Palpeoz., pi. 19, fig. 5. 



MonticuUpora frondosa, Edwards and Haime, Brit. Foss. Corals, p. 265. 



Corallum forming erect, flattened, undulating expansions, polypiferous 

 on both sides, of unknown but considerable height, and varying from 

 less than one line to three lines in thickness. Calices sub-circular, from 

 eight to ten in one line, almost or quite half their diameter apart, sepa- 

 rated by numerous very small cylindrical tubuli, which render the 

 spaces between the corallites minutely porous. Surface with stellate or 

 sub-circular spaces, which may either not project at all, or may be ele- 

 vated in the form of low, rounded tubercles, and which are occupied by 

 minute tubuli similar to those which separate the ordinary tubuli. 

 Often the corallites immediately surrounding these spaces are larger 

 than the average, the tubercles being usually arranged in irregular 

 diagonal lines, and placed at distances of about one line apart. 



I am not at all satisfied that the specimens from which the above de- 

 scription is drawn are really referable to the form described by D'Orbigny 

 under the name of MonticuUpora frondosa; but not having at this 

 moment access to this author's description, I provisionally describe our 

 examples under this name. Should they prove to be distinct, the name 

 of Chsetetes Ohioensis might be applied to them. I am also uncertain 

 whether some of the thinner expansions which I have here described 

 along with the more robust forms, do not constitute part, at any rate, of 

 the Chsetetes {Ptilodictya) pavonia of D'Orbigny. 



This species represents C. sub-pulchellus, Nich., in the ramose series, 

 but is distinguished from it not only by its frondescent mode of growth, 

 but also by the much greater development of the system of interstitial 

 tubules which it exhibits, the tubuli in the latter being confined to the 

 tubercular spaces, and not existing between the ordinary corallites. 



Man}' examples of this species appear to have attained a large size, 

 and are now only to be found in a broken condition. Mr. U. P. James, 

 however, has furnished me with a number of nearly perfect specimens, 



