194 PALEONTOLOGY OF OHIO. 



half a line transversely and two-thirds of a line measured vertically, 

 and they are either solid at their summit, or carry a few excessively 

 small cylindrical tubuli, with or without one or more of the ordinary 

 corallites. 



This form is very readily distinguished from the typical examples of 

 C. Dalei, Edw. and H , by the slightly smaller calices, the smaller num- 

 ber of the intermediate tubuli, and the characters of the surface tubercles, 

 which are not conical or prominent, and which are not covered with 

 corallites of the ordinary size. Nevertheless, I do not feel sure that 

 C. approximalus can be regarded as more than a very distinct variety of 

 C. Dalei, to which it is certainly closely allied, and to some forms of 

 which it presents a very close resemblance. 



Locality and position : Cincinnati group, Cincinnati, Ohio. Collected by Mr. U. P. 

 .James. 



Ch^etetes atteitus, Nicholson. 



Plate 21, fig. 4. 



Corallum composed of sub-cylindrical branches, which divide at short 

 ^intervals, and have a diameter of from four to. seven lines. Corallites 

 with thin walls, sub-eqiial, polygonal, from eight to ten in the space of 

 •one line. Some of the corallites are smaller than the others, but there 

 is apparently a complete, or almost complete, absence of excessively 

 minute tubuli interspersed amongst the larger tubes. Surface exhibit- 

 ing numerous minute, solid, quadrangular, or conical eminences, placed 

 at the point of junction of five or six corallites, and not carrying any 

 ■ cells themselves. These singular prominences are usually closely set, 

 four or five of them occupying the space of one line. 



This species is distinguished from all the preceding forms by its thin- 

 walled corallites, the absence of very minute tubules intercalated 

 amongst the ordinary corallites, and the minute, crowded, solid prom- 

 inences with which the surface is studded. At first sight, I was disposed 

 to think' that its peculiar appearance might be due to we'&.thering, and 

 that it might really be referable to some other species. A close examin- 

 ation of the specimens, however, has induced me to reject this view. 



Locality and positicm : Cincinnati group, Cincinnati, Ohio. Collected by Mr. U. P. 

 James. 



