PLATE II— Continued. 



DiCRANOGBAPTUS RAMOSUS, HaLL. 

 I^GraptoKfhus ramosiis, Paleontology of Xew York, Vol. 1. page 37. and Geology of Canada, page 200.) 

 Fig. 18. The lower part of a frond, in which the base is entire, with the bifurcation above 

 (natural size). 

 " 19. The bifurcating portion, with a part of the simple stipe, showing the cells on one side as 

 they are usually seen when flattened in the slate; or on one portion-of this there 

 are oval pustules, a feature sometimes observed in this species. The opposite 

 side gives the appearance of the cellules when flattened and compressed, partially 

 against the aperture (six diameters). 

 " 20. An enlargement from below the bifurcation, showing the more perfect form of the 

 aperture, with the spines proceeding from the exterior surface above the aperture 

 (enlarged to six diameters). /• 



" 21. A young individual or germ, supposed to be of this species, showing the basal processes 

 and the partially developed cellules at the upper part. 



