666 MR K. KIDSTON AND MR D. T. GWYNNE-VAUGHAN ON 



Plate IV. 



Fig. 18. Thamnopteris Schlechtendalii. Departing leaf-truce xylem still within endodermis of stem 

 stele. xl5. (Slide 1279.) 



Fig. 19. Thamnopteris Schlechtendalii. Free leaf-trace in close proximity to stele. x 15. (Slide 

 1279.) 



Fig. 20. Thamnopteris Schlechtendalii. Leaf-trace showing first appearance of parenchyma on adaxial 

 side of the protoxylem. x 15. (Slide 1279.) 



Fig. 21. Thamnopteris Schlechtendalii. Leaf-trace with small island of parenchyma. x 15. (Slide 

 1279.) 



Fig. 22. Thamnopteris Schlechtendalii. Leaf-trace with large island of parenchyma. x 15. (Slide 

 1279.) 



Fig. 23. Thamnopteris Schlechtendalii. Leaf-trace with the island of parenchyma just opening out to 

 a bay. x 15. (Slide 1280.) 



Fig. 24. Thamnopteris Schlechtendalii. Leaf-trace with open bay of parenchyma ; protoxylem spreading 

 out. x 15. (Slide 1280.) 



Figs. 25, 26, and 27. Thamnopteris Schlechtendalii. Leaf-trace with two protoxylems. Note a few 

 centripetal trachese in front of protoxylem in fig. 26. x 15. (Slides 1279 (figs. 26 and 27) and 1286.) 



Fig. 28. Thamnopteris Schlechtendalii. Leaf-trace with several protoxylems. x 15. (Slide 1280.) 



Fig. 29. Thamnopteris Schlechtendalii. Leaf-trace becoming reniform ; S. s., secretory sacs. x 15. 

 (Slide 1280.) 



Plate V. 



Fig. 30. Thamnopteris Schlechtendalii. Leaf-trace just departing; excentric protoxylem. x 15. 

 (Slide 1279.) 



Fig. 31. Thamnopteris Schlechtendalii. Free leaf-trace with excentric protoxylem. x 15. (Slide 

 1279.) 



Fig. 32. Thamnopteris Schlechtendalii. Leaf-trace with bay of parenchyma in front of excentric 

 protoxylem. x 15. (Slide 1280.) 



Figs. 33, 34, and 35. Thamnopteris Schlechtendalii. Leaf-traces showing double mesarch protoxylems. 

 x 22. (Figs. 33 and 35, slide 1279 ; fig. 34, slide 1280.) 



Fig. 36. Thamnopteris Schlechtendalii. Transverse section of a portion of an outer petiole to show 

 general tissues, muc. s., mucilage sacs ; res. c, zone of resistant cells ; i. par., inner parenchyma ; o. par., 

 outer parenchyma: Scl., sclerotic ring; pet. I., petiolar limit. x 15. (Slide 1282.) 



Fig. 37. Thamnopteris Schlechtendalii. End of the leaf-trace under higher power. Lettering as in 

 fig. 36. x 30. (Slide 1283.) 



Fig. 38. Thamnopteris Schlechtendalii. Part of leaf-trace under still higher power to show mucilage 

 sacs. Lettering as in fig. 36. x 55. (Slide 1282.) 



Fig. 39. Thamnopteris Schlechtendalii. Transverse section of free leaf-trace showing two root steles 

 arising from the adaxial corners. x 20. (Slide 1281.) 



Fig. 40. Tliamnopteris Scldechtendalii. Transverse section of a root in its passage through the leaf- 

 coating, x 30. (Slide 1289.) 



Plate VI. 



Fig. 4 1 . Bathypteris rhomhoidea. Surface view of the type specimen. (Photograph by Mons. R. Koch ; 



forwarded by Mons. M. Zalessky.) Half nat. size. 



Fig. 42. Bathypteris rhomhoidea. Transverse section of specimen. x 2. (Slide 1292.) 



Fig. 43. Bathypteris rhomhoidea. Transverse section of an outer petiole. x 6. (Slide 1292.) 



Fig. 44. Bathypteris rhomhoidea Transverse section of a petiole closer in, showing increased amount 



of internal sclerenchyma. int. sc, internal sclerenchyma ; i. par., internal parenchyma; o. par., outer 



parenchyma. x 6. (Slide 1291.) 



