96 EXPLANATION OF PLATE 56*. 



Fig. 9. Vertical section of the dome-shaped trunk of 

 Stigmaria, shewing the relative position of the 

 branches. (Lindley and Hutton.) 



Fig. 10. Restored portion of a branch of Stigmaria, 

 shewing the manner in which the long cylindrical 

 leaves proceeded from the tubercles around its sur- 

 face to the length of many feet. In front, extend- 

 ing from a. to h. is seen the depression adjacent to 

 the internal eccentric woody axis a. From h. to c. 

 this axis is laid bare by the removal of a portion of 

 the sandstone. This part of the axis is drawn from 

 a specimen in the Oxford Museum. Scale one- 

 seventh. (Original.) 



Fig. 11. Fragment of a branch of Stigmaria, shewing 

 the character of the Tubercles, which formed arti- 

 culations with the bases of the leaves. The enlarge- 

 ment of the leaf towards its base («) seems to have 

 been calculated to strengthen this part, and to afford 

 space for the articulating socket. This socket 

 formed, with the spherical tubercle, an universal ball 

 and socket joint, admitting of motion in every di- 

 rection to a long cylindrical leaf floating in water. 

 Scale one-half. (Sternberg.) 



Plate m^", V. I. p. 483 et seq. 



Appearances presented by longitudinal and transverse 

 sections of recent and fossil Coniferous woods, cut into 

 thin shces, and magnified 400 times. (Nicol.) 



Fig. 1. Longitudinal Section of Pinus Strobus, cut pa- 

 rallel to a medullary ray. 



Fig. 2. Transverse Section of the same. 



a. a. Portions of concentric annual layers. 



Fig. 3. Longitudinal Section of Araucaria Cunninghami. 



Fig. 4. Transverse Section of the same. 



