I02 LOWER PENINSULA. 



CYATHOPHYLLUM SCYPHUS, N. Sp. 



Conical polyp cells, symmetrically curved, or irregularly constrict- 

 ed and geniculated, pointed, or with a broad scar of attachment. 

 Calyx deep, spacious, with erect margins ; bottom narrowing into 

 an obtuse point, or somewhat flattened. Lamellae linear, equal 

 near the margins, but unequal in length, the larger ones uniting in 

 the centre. The two lateral and the apertural gaps always plainly 

 indicated ; particularly distinct is the apertural gap, which has no 

 determined position with regard to the curvature of the polyp cells. 

 The surface of the lamellae is smooth ; their interstices filled with 

 vesiculose plates. The central area is transversely septate, by 

 compound vesiculose diaphragms. Number of lamellae in calyces 

 three and a half centimeters wide, 125 to 130. Polyp cells of larger 

 size, measuring about two inches across the calyx and about three 

 inches in length. Surface longitudinally ribbed by septal furrows, 

 and intermediate rounded carinae. Found in great numbers in 

 silicified condition in the lower beds of the Hamilton group, at Long 

 Lake, north of Alpena. LtU—^ 



Plate XXXV., Lower row. — The two fight -hand specimens. 

 One exhibits a view of the calyx, with distinctly visible indication 

 of the apertural and the two lateral gaps ; the other gives a side 

 view of a polyp cell. 



CYATHOPHYLLUM GENICULATUM, N. Sr. 



Large conical polyp cells of much interrupted growth by smaller 

 constrictions and by deeper abrupt truncations of the old calyces, 

 and renewed growth from their centre of a new calyx in consider- 

 ably deflected direction, often making a perfect right angle with 

 the old cell, which interruptions, frequently repeated, result in the 

 production of distorted, geniculated, conico-cylindrical polyp stems. 

 The basal portion of these stems exhibits sometimes a small scar 

 of attachment at the pointed end ; at other times broad scars, ex- 

 tending some distance upward along the sides, are noticed on the 

 lowest cell with truncate base. The latter more permanently at- 

 tached stems are usually of a more regular, straight, conico-cylin- 



