PLATE XV. 



Blothrophyllum decorticatum, Billings (page 171). 



Figure 1. Longitudinal section of a type specimen from the county of Haldimand, 



Ont. 

 Figure la. Transverse section of the same. 



Omphyma Eriphyle, Billings (page 180). 



Figure 2. Type specimen from Anse a la Barbe, Baie des Chaleurs, Que. ; reduced one" 



half. 

 Figure 2a. Longitudinal section of the same. 

 Figure 26. Transverse section of the same. 



Arachnophyllum pentagonum, Goldfuss (page 181). 



Figure 3. Part of the calicular surface of a specimen from Grand Manitoulin Island, 



Lake Huron. 

 Figure 3a. Septal ridges showing the double rows of pore-openings ; magnified four 



times. 



Arachnophyllum mamillare, Dale Owen (page 182). 



Figure 4. Part of the upper surface of a specimen from Grand Manitoulin Island, 

 Lake Huron. 



