Explanation of Plate 8. 



Figure 1. — Photograph of the original Gotland specimen figured by Goldfuss and 

 now deposited in the museum of the university of Bonn; natural 



size. Very kindly prepared by l>r. Carl Schhiter. 



Figure 2. — A vertical section of ChonophyUum maghificum through the outer area, 

 showing the septa formed of delicate superposed layers, ruder a 

 magnifier the flat faces of the supporting processes may be seen as 

 they pass upward through the successive septal lamina'. Between 

 the broad septa are the narrow, vesiculose interseptal cavities. Mag- 

 nified 2 diameters. 



Figure 3. — A view of the under side of the septal layers taken from a large drift 

 specimen of C. magnificum. The form and arrangement of the sup- 

 porting processes, as seen in cross-section, are here shown. In two 

 places near the top of the figure the layers in adjoining septa are 

 seen to be 'continuous through the intervening interseptal cavity, 

 arching upward and assisting in the formation of the vesicular 

 structure. Magnified 2 diameters. 



Figure 4.— A view of the narrow interseptal cavity, showing the vesicles in C. 

 magnificum. The coarser vesicles are probably formed by the septal 

 layers as shown in figure 3. Magnified H diameters. 



Figure 5.— Much of the structure of C. magnificum is shown in this figure. The 

 lower portion is the base of the specimen and the upper is the outer 

 edge of the calyx, the section being vertical and very near the center. 

 Near the top of the figure, along the upper side, are shown the vesi- 

 cles of the interseptal cavity, and below them a side view of the 

 septal layers and the edges of the supporting processes. A view of 

 the side face of the septum, with its blunt granulations, appears over 

 the middle third of the figure, while at the bottom is seen the thin, 

 angularly wavy septa of the central area. The irregular transverse 

 leaflets, instead of tabulae, here till the interseptal cavities. Magni- 

 fied l 1 , diameters. 



Figure 6.— ChonophyUum pseudohelianthoides, n. sp. Upper Silurian, Conjepruss j 



Bohemia ; natural size. 



Figure 7. — ChonophyUum greenei, n. sp. Niagara, Beargrass creek, Louisville, Ken- 

 tucky : natural size. 



.I'M', 



