lNDlfVNf\ PfVLfV&ONTObOGY. 



HELIOPHYLLUM O S C U L A T U M, N. Sp. 



Plate 1, Fig. 1 and Plate 2, Figs. 1-2-3. 



Corallum simple, or compound, rapidly inereasing.by calicular gemmation. 

 Height varying in ditferent examples from forty to eighty millimeters. Diam- 

 eter of calyx from thirty to forty millimeters. Exterior with rough annula- 

 lations and wrinkles, caused by intermittent growth. Tabuhe numerous and 

 closely arranged, elevated in the center of the calyx, from live to eight millime- 

 ters or more. Number of lamella? from seventy to eighty, alternating in 

 length, rounded and uniform in size at the margin, for about ten millimeters 

 nearly flat, then abruptly descends to the bottom of the calyx, where the short 

 ones terminate; the longer ones continue coalescing, fasciculating and twisting 

 into a rough prominence on the elevated tabula?. Denticulations moderately 

 course, ten in the space of seven millimeters. Fossette in some examples well 

 defined, in others very obscure. 



Found in the upper Devonian (Hamilton group), near Charlestown, and 

 at the different cement quarries in Clark county, Indiana, and at Crab Orchard, 

 Kentucky, now in the collection of the author. 



HELIOPHYLLUM N A N U M , N. Sp. 



Plate 1, Figs. 2-3-4. 



Corallum simple, oblique, with a broad scar at the base of attachment; 

 rapidly increasing in diameter to the margin of the cup. Calyx broadly cam- 

 panulate. Exterior with sharp annulations and constrictions caused by inter- 

 mittent growth. Length varying in different individuals from fifteen to twenty 

 millimeters. Diameter of calyx twenty to twenty-five millimeters, depth ten 

 to fifteen millimeters. Number of lamell* eighty, alternating in size and 

 length, the short ones gradually disappear before reaching the bottom of the 

 calyx. The longer ones become elevated and sharp as they gradually descend 

 to the center of the calyx, where they abruptly terminate. In some examples 

 they coalesce with the lamellie on the opposite side, twisting, and slightly ele- 

 vated, into a rough crest, Denticulations prominent in some places ; others 

 broken away or faintly indicated, Fossette well defined, consists of a deep 

 depression at the edge of the elevated space in the bottom of the calyx and 

 extends to the anterior margin. Situated in the fossette there is one conspicu- 

 ous lamelke, extending from the bottom of the fossette to the margin of the 

 calyx, The adjacent lamellaj as they descend about one-third the distance 

 from the margin coalesce, and again at about two-thirds the distance from the 

 margin, and on reaching the bottom of the cup they coalesce the third time. 



