Ill] 



ARTHROSTIGMA 



27 



/ ^ 



Fig. 8. Arthrostigmagracile, Dawson, 

 from the Lower Old Red Sandstone 

 of Scotland. (Nat. size.) After Kid- 

 ston (1893). 



4 .. f 





:/ 



Fig. 9. Arthrosiigma gracile, Dawson, 

 from the Lower Devonian of Roragen, 

 Norway. After Halle (1916). 



