PLATE XIV. 



Fig. 68. — Fragment of a Stigmarian root split longitudinally. Exterior of 

 medulla, a. Long section of the vascular cylinder, b, b. Primary medullary rays 

 passing horizontally through the vascular cylinder, b'. Cortex replaced by in- 

 organic matrix, d, d. Author's Cabinet. (Page 37.) 



Fig. 69. — Exterior of the vascular cylinder of a Stigmaria, from Burntisland. 

 Nat. size. Showing the large peripheral orifices of the primary medullary rays, b, b, 

 intermingled with a few rootlet-scars. Author's Cabinet. (Page 37.) 



Fig. 73. — A normal portion of a Stigmarian root deprived of its rootlets. 

 Cavity left by the disappearance of the vascular cylinder, b, Nat. size. Author's 

 Collection. (Page 38.) 



Fig. 75. — Cast of the outer surface of a Stigmarian bark which has been 

 in the condition of the specimen, Fig. 74, and is illustrated by the diagram, 

 fig. 76, Plate XII. Nat. size. Author's Collection. (Page 38.) 



Fig. 77. — External surface of a Stigmarian bark, like Fig. 74, modified by 

 shrinkage or compression. Nat. size. Author's Collection. (Page 40.) 



