EXPLANATIONS OF PLATE XXL 



Ptilograptds plumos0Sj page 140. 



Fig. 1. A fragment which is three times branched. 

 " 2. A slender simple branch. 

 " 3. An enlargement from the specimen fig. 1. 



" 4. A further enlargement of a portion of the same ; some of the branches showing 

 markings like cell-apertures. 



Ptilograptus Geinitzianus, page 140. 



Fig. 5. A branching fragment showing the celluliferous side. 

 " 6. A fragment which is irregularly branched, showing the non-celluliferous side. 

 " 7. A single branchlet of the same species. 

 " 8. An enlargement from fig. 5, showing the cell-apertures. 



Thamnograptus Anna, page 141. 

 Fig. 9. A fragment of the species, of the natural size. 



