228 PALEONTOLOGY OF OHIO. 



the main calice. The true calice varies from two to three lines in diam- 

 eter. As seen in the inner cup, or true calice, there are from forty to 

 forty-six slender septa, alternately large and small, united with one 

 another laterally by transverse dissepiments. In the space between the 

 two walls the septa are often imperfectly developed, or are so united with 

 one another and broken up by dissepiments as to give rise to a loose and 

 open vesicular tissue. 



This form is readily distinguished from all the other sjoecies of Acervu- 

 laria with which I am acquainted by the strong and well-marked outer 

 and inner walls, the great development of the septa within the inner 

 cup, the general proportions of the corallites, and the number and in- 

 equality in size of the septa. 



Position and locality: Clinton gi"Oup, Yellow Springs, Ohio. 



Eridophyllum Simcoense, Billings. 



Eridophyllum Simcoense, Billings; Canadian Journ., new ser., Vol. IV., p. 132, 1859. 

 Eridophyllum Simcoense, Nicholson; Eeport on the Palteontology of Ontario, p. 34, 1874. 



Corallum forming colonies of cylindrical, straight, flexuous or crooked 

 corallites, from two to three lines in diameter, distant from one another 

 from one to three lines, and united by short, horizontal connecting pro- 

 cesses. The connecting processes are thick at their points of junction 

 with the corallites, and thin in the middle, and they are often, though 

 not universally, turned in the same direction in the same colony. Their 

 distance apart varies from two to six lines. The epitheca usually ex- 

 hibits encircling annulations of growth, along with vertical ridges cor- 

 responding with the septa. There is a well-developed central tabulate 

 area, into which the septa either do not penetrate at all, or extend but a 

 short distance. The septa are between forty and fifty in number, and 

 are alternately large and small. 



It is possible that this species may turn out, on a more extensive ex- 

 amination of specimens, to be identical with E. rugosum, Edw. and H., 

 from the Upper Silurian of the island of Gothland. 



Position and locality : Clinton group, Yellow Springs, Ohio. 



