138 LOWER PENINSULA. 



CYSTIPHYLLUM NIAGARENSE. 



CONOPIIYI.LUM NIAGARENSE, Hall. 



Conical polyp cells attached to other bodies at the base, and by 

 additional root-like prolongations from the sides. Stems elongated, 

 subcylindrical, or shorter turbinate, annulated by superficial con- 

 strictions with tortuous flexions, or by periodical total interruptions 

 in the growth of a calyx, and the formation of a new cell from 

 within. The calyces are moderately deep, uniformly spreading 

 from an obtusely angustated bottom ; margins erect ; their surface 

 is blistered, and is radially striate by spinulose crests, developed in 

 some specimens with more distinctness than in others. The sur- 

 face of the polyp stems in well-preserved condition is longitudinally 

 ribbed by septal striae, but it often happens that the outer walls 

 are destroyed, and that the stems are of rough exfoliated aspect, 

 exhibiting the concave side of the blisters composing the cell cups, 

 and the free edges of the single invaginated cups composing the 

 stems. 



Found in the Niagara group of Drummond's Island, at Point 

 Detour ; likewise in the Niagara group of Kentucky, Iowa, and 

 Indiana. 



Plate XLIX. — Fig. 3 represents several silicified specimens of 

 shorter turbinate and of more elongate tortuous form. The upper 

 right-hand and the lower left-hand specimens are found at Drum- 

 mond's Island ; the other two at Masonville, Iowa. 



CYSTIPHYLLUM AMERICANUM, Milne-Edwards. 



Single polyparia, surrounded by a perfect, concentrically wrinkled 

 epithecal wall, of conical, or, in the progress of growth, of horn- 

 shaped, curved, or straight cylindrical form. Dimensions of stems 

 very variable, from one to two inches in diameter, and in specimens 

 of cylindrical growth not unfrequently over one foot in length ; 

 other specimens have a much shorter turbinate form. Calyces 

 moderately deep, with explanate margins, equally tapering toward 

 the bottom, which is generally occupied by a few irregular blis- 



