PLATE III. 



Halysites catenularia, L. (page 68). 



Figure 1. Portion of an average specimen from Lake Temiscaming, Que., with 



corallites of average size. Natural size. 

 Figure la. Transverse section of two corallites of the same, showing the position of 



the tubules. Enlarged five times. 

 Figure 16. Corallites and tubules of the same, as seen in longitudinal section. The 



tabulae of the tubules are strongly arched whilst those of the 



corallites are generally flat or slightly concave. Enlarged five 



times. 

 Figure 2. Portion of a specimen from the Niagara of Ontario with corallites that are 



almost circular. Natural size. 

 Figure 2a. Transverse section of two corallites of the same showing the septal spines 



and the tubules. A longitudinal section of these corallites is 



similar to what is shown in fig. 16. Enlarged five times. 

 Figure 3. A natural longitudinal section ol a specimen from the Guelph formation of 



Ontario. Natural size. 

 Figure 3a. Transverse section of the corallites of the same. Natural size. 



Halysites catenularia, var. micropora, Whitfield (page 70). 



Figure 4. Portion of a specimen from the Niagara of western Ontario showing a 

 marked irregularity in the shape of the meshes. Natural size. 



Halysites catenularia, var. gracilis, Hall (page 69). 



Figure 5. The general form and arrangement of the corallites as seen in a specimen 



from East Selkirk, Man. Natural size. 

 Figure 5a. Corallites of the same, as seen in transverse section. Enlarged five times. 

 Figure 56. Corallites of the same, viewed in longitudinal section. The septal spines 



on the sides of the corallites appear as dots. Five times the 



natural size. 

 Figure 6. Portion of a specimen from Jack Head Island, Lake Winnipeg, in which 



the corallites are large and more than usually angular. Natural 



size. 

 Figure 7. Part of a specimen from Churchill Harbour, Hudson Bay, with very small 



corallites. Natural size. 



