J8. CONTRIBUTION TO 



lites unequal in size. With the margins of their calix expanding, from twenty 

 to twenty-five millimeters mdiatneter. Denticulations strong, one millimeter 

 or more apart. Fossette consists of a shallow depression at the edge of the 

 smooth space in the bottom of the calix, and continues to the anterior margin. 



The specific name is in honor of Prof. A. E. Seaman, professor of Natural 

 Science in the Michigan Mining School, Houghton, Michigan. 



Found in the lower Devonian (Corniferous group), at the Falls of the Ohio. 

 Now in the collection of the author, 



HELIOFHYLLUM FLOS, N. Sp. 



Plate 7, Figs. 6-7-8. 



Corallum simple, or composite, increasing by calicular gemmation, straight 

 or regularly curved. With rather a broad scar at the base of attachment, on 

 the side of the coral, there is a number of slender root-like prolongations, that 

 served for attachment to other objects for support. Height from ten to fifteen 

 millimeters, calix broad, from eight to fifteen millimeters in diameter. Num- 

 ber of lamelhe twenty-two, in the space of eight millimeters, unequal in size at 

 the margin, alternating below. Corallites slightly unequal in size, five milli- 

 meters in diameter. Depth three millimeters with a smooth space in the bot- 

 tom of the calix two or three millimeters in diameter. Denticulations very fine, 

 conspicuous, ten or twelve in the space of five millimeters. No fossette ob- 

 served in any of the examples examined. 



Found in the upper Silurian (Niagara group), at the Bear Grass Creek 

 Quarries, near Louisville, Kentucky. Now in the collection of the author. 



HELIOFHYLLUM P A R T I T U M, N. Sp. 



Plate 8, Figs. 7-8. 



Corallum composite, increase by calicular gemmation, corallites slightly 

 unequal in size, somewhat quadrangular, with their margins intimately connect- 

 ed, and occupying the entire diameter of the parent cup. Number of lamellae 

 sixty to seventy or more, varying in different corallites. In some, the lamellae 

 is very thin, and the denticulations are distant, and fine. In others the lamelhie 

 is numerous, coarse, and the denticulations are very much coarser, and more 

 numerous. Acute at the base of attachment, rapidly expanding in diameter to 

 the margin of the cup. Height twenty millimeters. Calix broadly bell-shaped, 

 varying in different individuals from twenty to fifty millimeters in diameter. 

 Exterior very rugged with deep constrictions, and wrinkles, caused by intermit- 

 tent growth. No fossette observed in any of the corallites. 



