PLATE XXVI. 



Fig. 1. — Surface of a specimen of Stromatoporella gramdata, Nich., of the 

 natural size. Devonian (Hamilton Formation), Arkona, Ontario. 



Fig. 1 a. — Tangential section of the same, enlarged about ten times. 



Fig. 1 b. — Vertical section of the same, similarly enlarged. 



Fig. 2. — Surface of a specimen of Stromatoporella Selwi/nii, Nich., enlarged. 

 Devonian (Corniferous Limestone), Port Colborne, Ontario. This figure is repeated 

 from PI. I, fig. 14, where it is referred to Stromatoporella gramdata, Nich. 



Fig. 3. — Tangential section of the same, enlarged about ten times. (The 

 section is slightly oblique.) 



Fig. 4. — Vertical section of the same, similarly enlarged. 



Fig. 5. — Tangential section of Stromatoporella socialis, Nich., showing part of 

 one of the astrorhizal cylinders, enlarged about ten times. Middle Devonian, 

 Teignmouth [pebble in the Triassic conglomerates]. 



Fig. 6. — Tangential section of another specimen of the same, from the same 

 locality, showing " Gaunopora-tubes." Enlarged about ten times. 



Fig. 7. — Vertical section of the preceding specimen, similarly enlarged. 



