DESCRIPTION OF SPECIES ANTHOZOA 273 



calyx. In most of the specimens there is a distinct alternation of strong 

 septa with much smaller septal ridges; but in one specimen which has 

 been studied, a larger individual, with more rapidly expanding sides than 

 usual, the alternating septal ridges are not present. The form of the calyx 

 also varies in different individuals ; it seems more commonly to be rather 

 broad and flat in the bottom, with a rather wide area across which the 

 inner ends of the septa do not pass, but in others it is deeper and more 

 pointed in the bottom, with a smaller clear space between the inner ends 

 of the septa. The somewhat subcarinate longitudinal ridge along the 

 longer convex side of the corallum toward the apex is present upon the 

 more typical individuals, but on others it is apparently absent. 



The identity of this coral with the original Z. cliff or dana described 

 from the hills south of Louisville, Kentucky, seems to be probable, 

 although an opportunity has not been afforded to compare typical exam- 

 ples from that region. The original figure of the species shows a speci- 

 men which is perhaps somewhat less curved at the apex than is usually 

 the case in the Fern Glen specimens, and the rim of the calyx has been 

 broken away so that the depth of the calyx can not be determined. 



ZAPHRENTIS WORTHENI n, sp. 



Plate 10, figures 20-21 



1890. Zaphrentis cliff ordan a ? Wortben, Geological Survey of Illinois, volume 

 8, plate 10, figure 1& (not figure 1). 



Description. — Corallum horn-shaped, subcircular in cross-section, 

 moderately curved, the sides diverging at an angle of about 30 degrees. 

 Surface rather smooth, marked by more or less infrequent annular wrin- 

 kles which are usually of small size. Rim of the calyx oblique ; the calyx 

 deep, contracted below, with a fossula of moderate depth and width 

 toward the shorter, concave side of the corallum; the major septa 25 to 30 

 in number, their inner extremities extending toward the center of the 

 floor of the calyx, but leaving a small central clear area; between the 

 major septa and alternating with them are an equal number of much 

 lower septa which are sometimes scarcely more than septal ridges. 



The dimensions of two individuals are: Length of corallum on convex 

 side, 54 millimeters and 40 millimeters; length of corallum on concave 

 side, 30 millimeters and 17 millimeters; diameter of calyx at rim, 21 

 millimeters and 18 millimeters. 



Remarks. — This species includes the straighter individual figured by 

 Worthen under the name Zaphrentis cliff or dana. It differs from the 

 coral to which that name is here restricted in its much straighter and 



