192 The Ohio Journal of Science [Vol. XVII, No. 6, 



Corallum simple, usually not exceeding 35 millimeters in length, but 

 occasionally attaining a length of 40 millimeters. Cardinal side strongly 

 flattened, giving the calice a subtriangular outline (Fig. 3D). Lateral 

 margins of corallum more or less strongly angular. Viewed from the 

 side, the transverse wrinkles are seen to incline from the cardinal side 

 strongly forward and downward, and the cardinal side is straight or 

 only moderately curved for the greater part of its length. Toward the 

 calice, the corallum frequently curves more strongly forward, (Fig. 3B), 

 and the outline of the calice becomes transversely oval or nearly circular 

 (Fig. 3H). At the same time, the lateral diameter of the corallimi 

 frequently becomes shorter, and sometimes the antero-posterior diameter 

 also becomes less, suggesting gerontic conditions. The two narrow 

 longitudinal ridges locating the cardinal septum usually are distinctly 

 defined along the lower half of the cardinal side of the corallum, but 

 become less conspicuous along the upper half. The alar septa are 

 located along the lateral angles of the corallum. 



From 25 to 30 larger septa line the interior of the calice, alternating 

 with which are an equal number of short septa confined to the upper 

 part of the calice. The cardinal septum is only slightly more conspicuous 

 than the remainder. Those septa which are intermediate between the 

 cardinal and alar septa tend to meet at the bottom of the calice, in the 

 more triangular forms, so as to present the appearance of two groups, 

 one on each side of the cardinal septum (Fig. 3K). In the calices 

 with more circular outlines, this tendency toward grouping is not 

 conspicuous, and it varies greatly in different individuals. Occasionally 

 the second or third one of the larger septa on the right and left of the 

 cardinal septum becomes more conspicuous than the rest, (x in Fig. 3K). 

 Together with the cardinal septum, they form a group of three somewhat 

 more prominent septa, chiefly in specimens retaining their triangular 

 outline even at the aperture of the calice. In most specimens, especially 

 those with a circular outline at the aperture, these septa are not more 

 conspicuous than the rest. 



In Anisophyllum trifurcatum, Hall, it is the two alar septa 

 which in conjunction with the cardinal septum, form a group 

 of three somewhat more conspicuous septa. 



In Ilolophragma calceoloides, the septa are not twisted 

 together at the center, as in Streptelasma, and the cardinal 

 septum is not located in a fossula, as in Zaphrentis. 



Typical Ilolophragma calceoloides occurs in layers c and d 

 of the Silurian of Gotland. It is recorded from the coast at 

 Wisby, Guisvard, Staf, Nyrefsudd in Tofta, Likkershamm, 

 Kristklint, Hallshuk, on west shore of Kapellshamn. 



The specimens here figured and described were obtained in 

 the upper part of the West Union formation, in the Silurian at 

 Hillsboro, Ohio. Here they are most abundant at the Zink or 



