126 Dr. W. C. Williamson on ^ 



Type of Rliytidolepis. 

 Cortical Layers. 



B. — p. 213, Fig. 39. Exterior surface of the Cortex. 



Prosenchymatous Zone. 



B. — Transverse. p. 212, Figs. 35-36, See C.N. 659, 



,, p, 213, Figs. 40 and 41. See C.N. 653. 



Longitudinal, p. 213, Fig, 42i, k. C.N. 654. 



Outermost Parenchyma and Leaf Cushion. 



B. — Transverse. p, 212, Figs. 35 and 36. See C.N. 659. 

 ,, p. 213, Figs. 40 and 41, See C.N. 653, 



Longitudinal, p. 213, Fig. 42I. 



Leaf-Trace, 



B. — p. 214, Fig. 42m, C.N. 464. 



For tangential sections of the cortical prosenchyma shewing tranverse 

 ones of these leaf-traces with pairs of parichnoid organs, see 

 657 and 662, 



Type of Sigillaria Renifonnis, not yet figured or described. 



C.N, 651, transverse section across two of the longi- 

 tudinal cortical ribs shewing the inner prosenchyma and 

 the outer parenchyma of the leaf-cushion. Within this is 

 a transverse section of a portion of secondary xylem strand 

 and the primary tracheal cylinder. These shew very 

 clearly the undulating line of junction between the two, 

 already referred to as being apparently a feature of at least 

 some of the Sigillarice. At the exterior of the secondary 

 xylem there is a very distinct young zone of secondary 

 exogenous growth. C.N. 652 shews two of the long 

 cortical ribs with sections of leaf-traces — but no trace of 

 adenoid organs. In the centre is a longitudinal section of 

 the secondary xylem strand with vertical rows of medullary 

 rays between the tracheae. 



STIGMARIA. 



That Stigmaria ficoides is the root of various species 01 

 Lepidodendron and Sigillaria is now well known, though 

 there appear to be forms of Stigmaria found in France 

 which differ from the English type in the number of the 



