INDIANA PALAEONTOLOGY. 28. 



flat, convex space in the bottom of the calix, from five to seven millimeters in 

 diameter. Situated in the center of the flat area, is a smooth space, horse-shoe 

 shaped, with vertical walls, three millimeters in diameter. At the margin of 

 the cups the lamella are equal in size, alternating below, the short ones extend 

 to the bottom of the calix, and gradually disappears ; the longer ones are slight- 

 ly elevated, and continue on the bottom of the cup, to the vertical wall, in the 

 center of the calix, and abruptly terminate. 



In some of the corallites, they have the decided appearance of prolific gem- 

 mation. In a vertical section, the corallites have the appearance of thin, 

 somewhat distant invaginated cups, caused by the contraction and expansion of 

 the periodical growth. 



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

 the Ohio. Now in the collection of the author. 



PTYCHOPHYLLUM GEMMATUM, N. Sp. 



Plate 12. Figs. 2-3. 



C'orallum rather small, simple, or composite, increasing by lateral gemma- 

 tion ; base rather broad, having root-like processes for attachment to some for- 

 eign bodies. Height varying in different examples, from twenty to thirty milli- 

 meters. Exterior with sharp constrictions, and wrinkles, caused by intermittent 

 growth. When decorticated, the longitudinal striae is distinct, about one 

 millimeter in thickness. Calix rather broad, bell-shaped, fifteen millimeters in 

 diameter. Depth ten millimeters. Number of lamellae, seventy-six in the 

 circumference of a calix, fifteen millimeters in diameter, alternating in length, 

 equal in size at the margin, the short ones not over five millimeters in length ; 

 the longer ones continue to the center of the calix, flexuous and slightly 

 twisted, but not elevated. No fossette visible. 



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

 ;the Ohio. Now in the collection of the author. 



PTYCHOPHYLLUM BENEDICTI, N. Sp. 



Plate 12. Figs. 4-5-6. 



Corallum simple, or composite, increasing by calicular gemmation, turbi- 

 nate, straight or irregularly curved. Acute at the base of attachment. Gradu- 

 ally, or in some examples, more rapidly expanding in diameter to the calix. 

 Height twenty-five millimeters. Calix broadly bell-shaped, twenty to thirty- 



