210 PALEONTOLOGY OF OHIO. 



Chetetes papillatus, McCoy. 



NebvMpora papillata, McCoy ; Ann. and Mag. Nat. Hist., 2d series, Vol. VI., p. 284, 



1850; Brit. Pal. Foss., pi. Ic, fig. 5. 

 Chietetes tuberculatus, Edwards and Haime ; Pol. Foss. des Terr. Palseoz., pi. 19, figs. 3, 3a. 

 Monticulipm-a papillata, Edwards and Haime ; Brit. Foss. Corals, pi. 62, figs. 4, 4a. 



Corallum forming an exceedingly thin crust, usually about half a line 

 thick, growing upon Brachiopods and other foreign objects. Surface ex- 

 hibiting rounded tuberosities, sometimes very slightly elevated, placed 

 about their own diameter apart, occupied by corallites of larger size than 

 the average. Corallites polygonal, thin-walled, somewhat variable in 

 size, but not having any very minute tubuli intercalated amongst them. 

 The average corallites are from eight to ten in the space of one line, 

 those occupying the tubercles being from five to six in one line. 



Our specimens agree well with the description given by McCoy of 

 Nebulipora papillata, but they differ somewhat from that given by Ed- 

 wards and Haime. Thus the tubercles in all the examples that I have 

 seen are rounded, not to any extent elongated or markedly compressed, 

 .and the larger corallites occupying these eminences are decidedly smaller. 

 The tubercles are not uncommonly perforated by regular and large circu- 

 lar perforations, which appear to be the mouths of vertical tubes, and 

 have a diameter of about half a line. This same phenomenon is very 

 ■conspicuous in many examples of 0. mammulatus, C. petropolitanus, 

 0. frondosvs, and other spedies of Chsetetes, and in many respects reminds 

 • one of the perforations produced by Cliona. I am not, however, prepared 

 to assert that this is their true nature. 



In its general characters C. papillatus, McCoy, approaches C. mammula- 

 tm, D'Orb.; but it is readily distinguished by its forming very thin 

 crusts, which are attached parasitically to the outside of submarine 

 bodies. It is easily distinguished from C. corticans, Nich., by the very 

 (long, narrow tubercles which characterize the latter. 



.Position and locality : Cincinnati group, Cincinnati, Ohio. 



Chetetes corticans, Mcholson. 



Plate 22, figs. 6, 6a. 



Corallum parasitic, forming a thin and expanded crust, less than one 

 ■ quarter of a line thick, or when in superposed layers attaining a thick- 

 ness of half a line. Surface exhibiting a number of long, narrow, com- 



