n. CONTRIBUTION TO 



diameter, thin and equal in size at the margin, alternating in length; the short 

 ones abruptly slope to the bottom of the calix and terminate ; the longer ones 

 become flexuous and gradually slope to the center of the calix, meeting those 

 of the opposite side, and abruptly end. Fossette consists of a shallow, narrow 

 groove commencing in the bottom of the calix, extends a short distance on the 

 side of the cup, and gradully disappears ; position variable. Exterior with ir- 

 regular annulations and sharp constrictions, caused by intermittent growth, 

 when decorticated they have the appearance of a number of thin invaginated 

 cups. 



Found in the Upper Devoniou, (Hamilton group) near Charlestown, Indi- 

 ana. Now in the collection of the author, 



C Y S T I P H YL L U M C R A S S A T U M, N. Sp. 



Plate 5. Figs. 9, 10. 



Corallum simple, explanate. Composed of a series of thin, blistered, caly- 

 cinal cups, with a strong wrinkled epithecal crust on the under side, and hav- 

 ing a small flat scar at base of attachment. Diameter of corallum varies in 

 different individuals, from thirty to forty millimeters, with a thickness from 

 ten to twenty millimeters. Calix shallow, slightly concave, and strongly vesic- 

 iilose, the largest cysts are near the bottom of the cup. Near the margin there 

 is numerous fine stria3, but gradually disappears before reaching the bottom of 

 the calix. 



Found in the Upper Devonian, (Hamilton group) near Charlestown, Indi- 

 ana. Now in the collection of the author. 



C Y S T I P H Y L L U M G E M M A T U M, N. Sp. 



Plate 6. Figs. 2, 3, 4. 



Corallum simple, or compound, rapidly increasing by calicular, or lateral 

 gemmation ; in some examples they have a broad scar at the base of attachment, 

 in this case some of them have rootlets that show evidence of being attached to 

 some foreign body, and in some examples the base of attachment is acute. 

 Height varying in different individuals from one to six inches. The exterior 

 is very rugged and deeply constricted, and when decorticated appears as thin 

 invaginated cups. The calix is so variable that in twenty examples no two 

 would appear alike; when not interrupted by the new growth, it is somewhat 

 bell-shaped, and has a depth of one inch, with numerous fine septa, eight in 

 the space of ten millimeters. Small cysts appear near the margin of the cup, 

 but are larger in the bottom; in some other examples, the cysts are large 

 throughout the calix, entirely obscuring the septa. 



