PALEONTOLOGY. 1 25 



DIPHYPHYLLUM PANICUM. 

 Synon., Cyathophyllum panicum, Winchell. 



Large colonies of diverging, partially contiguous cylindrical stems 

 of about one centimeter in diameter, multiplying by prolific caly- 

 cinal gemmation. Stems longitudinally striate and transversely 

 wrinkled by lines of growth, and, periodically, by deeper incid- 

 ing constrictions. Calyces deep, with steep side walls and slightly 

 expanded margins. Bottom of calyces occupying about one third 

 of the diameter of the stems, formed of vesiculose compound dia- 

 phragms, which are only in their peripheral circumference intersect- 

 ed by vertical lamella. Lamellae crenulated at the edges and deco- 

 rated on the sides with arched carinas, from forty to fifty in the 

 circumference of a calyx. Peripheral area filled with small inter- 

 lamellar vesicles ; the two areas are not defined from each other 

 by an intervening wall. Found in the upper part of the Hamilton 

 group, in the lime quarries near Petosky, and on Little Traverse 

 Bay. 



Plate XLVIL, Fig. 3. — Two fragments, one exhibiting a vertical 

 section through the stems, the other giving the exterior surface 

 of the stems. 



DIPHYPHYLLUM GIGAS, N. Sp. 



Large cylindrical stems, sometimes over one inch in diameter, 

 growing in cespitose colonies, and multiplying by prolific calycinal 

 gemmation of the stems. Surface covered with annular wrinkles, by 

 which the stems attach themselves to one another. Longitudinal 

 septal striae very distinct. Calyces deep, with steep side walls and 

 gently expanded margins, surrounded by about eighty subequal 

 lamellae crenulated at the edges by the development of arched 

 lateral carinae. Interlamellar interstices of the outer area filled 

 with small, transverse, vesiculose plates. Bottom of calyces formed 

 by flat diaphragms, smooth in the centre, and intersected in the 

 circumference by the vertical lamellae ; no defining walls between 



