EXPLANATION. 
Due to the arrangement of the material, the binders found it 
impossible to place the plates of Wenzel, Gates and Wood any- 
where except at the end of the volume. These plates are not 
named, only numbered. They come in three series. 
Series 1, numbered consecutively Plate I (fig. 1) to Plate 
XI, (fig. 19) goes with Wenzel’s paper. 
Series 2, numbered 2 to 20, goes with Wood’s paper. 
Series 3, numbered V to XXI b, goes with Gates’ article. 
