PLATE XVI. 



Acrophyllum Oneidaense, Billings (page 175). 



Figure 1. Side view of a specimen from the Corniferous formation of Ontario, showing 

 the calyx in perspective and part of the tabulate and vesicular areas 

 in longitudinal section. 



Figure 2. Transverse section of another specimen. 



Arachnophyllum eximium, Billings (page 184). 



Figure 3. Part of the calicular surface of the type specimen from West Point, Grand 



Manitoulin Island, Lake Huron. 

 Figure 3a. Longitudinal section of one of the corallites of the same ; twice the natural 



size. 

 Figure 4. Transverse section of a corallite of another specimen from Grand Manitoulin 



Island ; enlarged two diameters. 



Chonophyllum Belli, Billings (page 186). 



Figure 5. Side view of the type specimen fiom the east side of the village in the bight 

 of West Bay, Grand Manitoulin Island, Lake Huron. 



Figure 6. The calyx of another specimen, as seen from above ; from half a mile north- 

 west of Portage Bay, Lake Manitou, Grand Manitoulin Island, 

 Lake Huron. 



Cystiphyllum Niagarense, Billings (page 190). 



Figure 7. Side view of a specimen from Cockburn Island, Lake Huron (type of C. 

 Huronensc). 



