20J- CONTRIBUTION TO 



curved, or sometimes geniculated. Acute at the point of attachment, or some^ 

 examples have a broad scar at the base. Height varying in different examples. 

 from thirty to seventy millimeters. Diameter of calix thirty to fort}' millime- 

 ters. Depth twenty millimeters. Number of lamellae one hundred in the cir- 

 cumference of a calix twenty millimeters in diameter, thin and sharp, and 

 slightly unequal in size at the margin, growing thinner and alternating below,, 

 abruptly sloping to the bottom of the calix, where the primary ones coalesce 

 and blends with the tabular and terminate, leaving a smooth oblique space in 

 the bottom of the calix twelve or fifteen millimeters wide. The secondary la- 

 mellae is confined to the wall and scarely ever exceed twelve or fifteen millime- 

 ters in length. The exterior, when decorticated, is very rugose, having the 

 appearance of close, or in places of distant invaginated calices. The primary 

 fossette is situated on the side of the longest cvirviture of the coral, commencing 

 at the margin of the smooth oblique space in the bottom of the calix and ex- 

 tends to the anterior margin. There are two rudimentary fossettes, situated at 

 right angles to the principal one, but neither of these extends to the margin of 

 the calix. Denticulations rather fine, frequently they are destroyed by the- 

 weathering of the coral. 



Found in the Middle Devonian, (upper Helderberg group) at the Falls of 

 the Ohio. Now in the collection of the author. 



ZAPHRENTIS CALIGULUS, N. Sp. 



Plate 59. Figs. 8, 9, 10, 11. 



Corallum simple, turbinate, straight or slightly curved, acute at the point 

 of attachment. Height sixty millimeters, for about half the length compressed 

 and slightly curved, then abruptly rounding to the margin of the calix, in some 

 examples instead of rounding to the margin they become somewhat quadrilat- 

 eral. Exterior with broad, shallow, rounded annulations and wrinkles, caused 

 by intermittent growth. Calix broadly bell-shaped, or quadrilateral, forty-five 

 millimeters in diameter. Depth twenty millimeters. An elevated space in the 

 bottom of the calix, occupied by the tabulae, thirty millimeters long and twenty 

 millimeters wide in a calix forty-five millimeters in diameter. Number of la- 

 mellte one hundred and fourteen in the circumference of a calix forty millime- 

 ters in diameter, equal in size and rounded at the margin, alternating and 

 growing thinner below, gradually sloping to the bottom of the calix, where the 

 short ones terminate ; the longer ones continue for a short distance and ab- 

 ruptly turns upwards for four or five millimeters, then turn toward the center 

 of the calix, coalescing and fasciculating, and abruptly ends, leaving a smooth 

 depressed space in the center of the calix, two millimeters wide and four or five 

 millimeters long. Fossette consists of a deep depression at the margin of the 



