THE ANATOMY OF TODEA. 259 
EXPLANATION OF THE PLATES. 
PLATE 27. 
Fig. 1. Todites Williamsoni. From a specimen in the Geological Museum, Cambridge. 
Figs. 2 & 3. Todea barbara. From plants in the Kew Herbarium. 
Fig. 4. CladopAlebis denticulata. From a specimen in the Geological Museum, Cambridge. 
5. Todea barbara. From a plant in the Kew Herbarium. 
6. Kidstonia heracleensis. Portion of fertile pinnule. (x 30.) After Zeiller. 
7. Kidstonia heracleensis. Sporangium seen from the side. (x40.) After Zeiller. 
Figs. 8 & 9. Todites Williamsoni. Sporangia. (x65.) After Raciborski. 
Fig. 10. Todea hymenophylloides. Young plant. 
ll. Todites Williamsoni. Fertile frond: from a specimen in the Geological Museum, Cambridge. 
12. Discopteris Rallii. Sporangium seen from above. (x40) After Zeiller. 
13. Todites Williamsoni. Fertile pinnule. (x4.) After Raciborski. 
PLATE 28. 
Fig. 14. Todea superba. Transverse section through the outer part of the stele, near the apex of the 
stem. en=endodermis; pr, cells between the endodermis and the sieve-tubes (pericycle) ; 
s-s, sieve-tubes ; zp — xylem-parenchyma ; mz —unlignified metaxylem. (x 200.) Page 242. 
15. Todea hymenophylloides. Transverse section near the apex of the stem. px=protoxylem. 
(x 9200) P. 242. 
16. Todea barbara. Transverse section. t=innermost elements of the region pr of fig. 14, the 
tangentially elongated elements of Zenetti and the protophloem of Faull. (x170.) P. 242. 
17. Todea hymenophylloides. Transverse section through an older part of the stele than that from 
which fig. 15 was drawn. (x 170.) P. 249. 
18. Todea superba. Diagrammatic sketch of part of a transverse section close to the apex of the 
stem. (x 15) P. 243 : 
19. Todea superba. Transverse section through part of the stele close to the apex of the stem. 
None of the xylem elements are lignified. (x 120.) P. 242. 
20. Todea hymenophylloides. Diagrammatic transverse sections of the young stele, showing the 
form of the xylem tissue. 
21. Todea superba. Transverse section taken at a slightly lower T in the stem than that shown 
in fig. 19. (x 190.) P. 242. | 
22. Todea hymenophylloides. Transverse section of the stele near the tip of the primary root. 
(x 190) P. 241. 
23. Todea superba. Apical cell of the stem. (x 150.) P. 242. 
24. Todea hymenophylloides. Transverse section at a slightly higher level than fig. 22. (x 190.) 
P. 241. 
325. Todea hymenophylloides. Transverse section through the xylem and bia of the egen region 
of a young plant, at a higher level in the stele than fig. 24. m=pith. (x 200.) P 241. 
PLATE 29. 
Fig. 26. Todea barbara. Diagram of part of a transverse section of the stem. P. 243. 
27. Todea barbara. Pian oí the xylem strands in the stele. »+1—n+1\=leaf-traces ; pz, dotted 
lines showing the course of protoxylem strands. 
