AIR-BREATHERS OP THE COAL PERIOD. 91 



EXPLANATION OF PLATE I. 

 Footprints of Reptiles, fyc. 



Pig. 1. — Footprints discovered by Sir W. E. Logan, in the Lower Car- 

 boniferous beds of Horton Bluff, in 1841 ; reduced to one- 

 fourth of the natural size, (la) one of the impressions, natu- 

 ral size. 



" 2. — Footprints discovered by Dr. Harding, in the Lower Carbonife- 

 rous beds of Parrsboro'; one-fourth of the natural size. (2a) 

 Prints of fore and hind foot, natural size. This figure is 

 from a rubbing kindly taken for me by Prof. How, of Wind- 

 sor. 



u 3. — Footprints from the Coal Measures of the South Joggins ; 

 one-fourth natural size. (3 a) One of the impressions, natu- 

 ral size. 



" 4. — Smaller footprints from the South Joggins ; one-fourth of natu- 

 ral size. 



" 5. — Skin of a reptile, found with remains of a small Dendrerpeton, 

 in an erect tree at the Joggins. (a) Scaly portions ; (b) 

 Traces of hind leg? and small scales, (c) (d) Portions 

 magnified, showing scales. 



EXPLANATION OF PLATE III. 

 Dendrerpeton Acadianum. 

 Fig. 1. — Skull seen from below. 



" 2. — Inner tooth, magnified ; from the jaw, Fig. 17. 



M 3. — Tooth of intermaxillary, magnified ; from the bone in Fig. 13. 



" 4. — Series of inner teeth, less magnified. 



" 5. — Series of outer teeth of maxillary bone, Fig. 15, magnified. 



u 6, 7. — Sections of inner teeth. 



'■' 8. — Portion of bone of skull, outer surface, twice the natural size. 



" 9. — Super-temporal bone, twice the natural size. 



" 10. — Cross section of humerus ; (a) natural size ; (b) magnified ; (c) 

 portion more highly magnified, showing canals and bone 

 cells. 



" 11. — Bone cells, highly magnified. 



" 12. — Vomer ? with teeth ; (a) tooth magnified. 



" 13. — Intermaxillary with teeth. 



" 14. — Section of teeth of intermaxillary ; (b) magnified ; (a) portion 

 highly magnified. 



" 15. — Maxillary bone with teeth. 



" 16. — Mandible with teeth. 



" 17. — Fragment of skull, with (a) outer teeth of maxillary ; (b) in- 

 ner palatal teeth. 



" 18. — Cross section of a 3cale, magnified. 



