192 PALEONTOLOGY OF OHIO. 



to the exterior of other corals. This section of the genus is an exceed- 

 ingly natural one, and there is no reason to suppose that there is any 

 transition between it and any of the preceding groups. It is represented 

 in the Silurian deposits of Ohio by C. papillatiis, McCoy, C. corticans, 

 Nich., C. Ortoni, Nich, C. Newberryi, Nich., and C. petechialis, Nich. 



Chetetes Dalei, Edwards and Haime. 



Plate 21, flgs. 1, la.: 



Chsetetes Dalei, Edwards and Haime ; Pol. Foss. des Terr. Pal., p. 266, pi. 19, fig. 6. 

 Monticulipora Dalei, Edwards and Haime ; Brit. Foss. Corals, p. 265, note. 



Corallum branching, the stems cylindrical or elliptical, dividing dicho- 

 tomously at short intervals, sometimes reticulating, their average diam- 

 eter when full grown from three to four lines, but when immature from 

 one line to two lines. Calices in general six to eight in the space of one 

 line, polygonal, with moderately thick walls. A greater or less number 

 of exceedingly small calices always intercalated among the ordinary 

 corallites. Surface covered with conical, often sharply pointed, rarely 

 transversely elongated eminences or tubercles, which sometimes attain 

 a height of more than half a line, and which are placed at distances 

 apart of from half a line to nearly one line. Commonly these eminences 

 are arranged in irregular diagonal lines, and they are always occupied 

 by corallites which do not exceed the average in point of size. The sum- 

 mits of the tubercles, indeed, are not unfrequently solid, or are occupied 

 by corallites of less than the average size. 



The typical examples of this well marked and common species are 

 distinguished by the prominence of the closely arranged surface-tuber- 

 cles, which are exceedingly conspicuous, and are not drawn out into 

 transverse ridges, whilst the normal or average corallites are separated 

 by a great number of extraordinarily minute cylindrical corallites. The 

 larger sized tubes are thus surrounded by from three to six or more of 

 these intercalated tubuli, and they thus acquire a more or less circular 

 form. In other examples, however, which approach Ohastetes approxima- 

 tus, Nich., the tubercles are not so pronounced nor so sharply elevated; 

 whilst the corallites only exhibit a few minute tubuli placed occasionally 

 at their angles of junction. In both forms the branches are not uncom- 

 monly hollow, and it is not very rare for a certain amount of anastomosis 

 to take place between contiguous branches. 



Locality and position : Cincinnati group, Cincinnati, Ohio. 



