PLATE XX. 



Sigillaria vascularis, Binney. 



Fig. 1 (No. 39). Transverse section of the pith and internal radiating cylinder. 

 Magnified 4^ diameters. 



Fig. 3. Longitudinal section of the pith, internal radiating cylinder, and a portion 

 of the outside. Magnified 12 diameters. 



Fig. 3. Tangential section of a part of the internal radiating cylinder, showing the 

 vascular bundles and medullary rays. Magnified 16 diameters. 



Fig. 4. Longitudinal section of a part of the outside radiating cylinder of elongated 

 cells or utricles. Magnified 12 diameters. 



Fig. 5 (No. 40). Transverse section of a small specimen from the "Bullion 

 Coal, " near Burnley, showing the pith and internal radiating cylinder. Magnified 9 

 diameters. 



In this and the following plates the same parts of the specimens figured are indicated by 

 the same letters, as follow : — 



a. The middle part, showing the central axis or pith, composed of large and small 

 scalariform tubes, or utricles and cells, but occasionally more or less separated by fine 

 orthosenchymatous tissue. 



b. The small scalariform tubes forming the inner portion of the woody cylinder. 



c. The large scalariform tubes forming the outer portion of the woody cylinder. 



d. The vascular bundles proceeding from the inner radiating cylinder, traversing 

 the outer radiating cylinder, and extending to the leaves and rootlets. 



d' . The medullary rays, formed of a single or double row of cells, seen in a 

 tangential section of the woody cylinder. 



e. The mass of parenchymatous tissue, at first (near the woody axis) of a coarse 

 and lax character, but becoming finer and denser as it proceeds outwards, until it becomes 

 prosenchymatous. 



/. The elongated tubes, or utricles, arranged in radiating series, forming the outer 

 zone next the epidermis. 



g. The epidermis of the plant, nearly always converted into coal. 



