'272 S. WELLER FAUNA OF THE FERN GLEN FORMATION 



ZAPHRENTIS CLIFFORD AH A Milne-Edwards & Eaime 

 Plate 10, figures 18-19 



1851. Zaphrentis cliffordana Milne-Edwards and Haime, Monog. des Polyp. 



Foss., page 329, plate 3, figure 5. 

 1860. Zaphrentis cliffordana Milne-Edwards, Hist. Nat. Corr., volume 3, page 



337. 

 1890. Zaphrentis cliffordana f Worthen, Geological Survey of Illinois, volume 8, 



page 75, plate 10, figure 1 (not figure lo). 



Description. — Coralhim simple, curved, horn-shaped, subcircular in 

 cross-section, expanding somewhat regularly, the sides diverging from the 

 apex at an angle of 35 to 45 degrees, subcarinate along the convex side to- 

 ward the apex ; the axis of the corallum describes a curve which approaches 

 the quadrant of a circle, but which is somewhat more rapidly curved to- 

 ward the apex. Surface marked by regular annular wrinkles of moderate 

 strength and by almost obsolete longitudinal ribs which correspond in 

 position with the septa. Calyx of moderate depth, with a broad base, 

 the fossula of moderate size and depth adjacent to the shorter side of the 

 corallum. Septa in a large individual with a calyx diameter of 20 milli- 

 meters, 35 in number without alternating smaller ones; another indi- 

 vidual, with a calyx diameter of 13 millimeters, has 24 stronger septa 

 with an equal number of small, low septal ridges alternating with them. 

 The septa do not reach the center of the calyx, but leave a smooth, clear 

 space in the bottom. 



The dimensions of two individuals are : Length of the longer side of 

 the corallum, 44 millimeters and 38 millimeters; length of shorter side 

 of corallum, 19 millimeters and 19 millimeters; diameter of calyx, 20 

 millimeters and 13 millimeters. 



Remarks. — Worthen has illustrated two specimens from the Kinder- 

 hook beds of Monroe county, Illinois, under the name Z. cliffordana, 

 which could only have been found in the Fern Glen beds near Valmeyer. 

 The two individuals are quite different in form and doubtless represent 

 distinct species, both of which have been commonly met with in the 

 recent collections from the Fern Glen beds at various localities. Only 

 the smaller and more curved specimen illustrated by Worthen (figure 1) 

 can be reasonably referred to Z. cliffordana, and it is with this coral that 

 the specimens here described are identified. The character which seems 

 to be most constant among the various individuals which have been 

 studied is that of the curvature of the corallum and the comparatively 

 smooth surface. The divergence of the sides of the corallum varies con- 

 siderably in different individuals, so that the diameter of the rim of the 

 calyx is variable, and the number of septa varies with the size of the 



