230 Yapp . — Two Malayan ‘ Myrmecophilous' Ferns . 
Fig. 20. Plan of main ventral gallery, showing lateral galleries (/.), and the 
position (a.) of the vertical galleries with respect to them. 
Fig. 21. Plan of the dorsal chambers, a. position of vertical gallery; b. outer- 
most branch of one of the chambers. 
Fig. 22. Median vertical longitudinal section of stem, (f nat. size.) 
Fig. 23. Vertical longitudinal section of stem, passing through the series of leaf- 
cushions of one side, i.e. across line c. c. in Fig. 20. (f nat. size.) 
Fig. 24. P. sinuosum , transverse section of stem, passing vertically through 
a leaf-cushion, d. a diverticulum of main gallery entering an incipient branch. 
(| nat. size.) 
Fig. 25. Ditto, passing through main gallery and also a blind dorsal gallery. 
(| nat. size.) 
Fig. 26. P. sinuosum, plan of dorsal chambers, a. is position of vertical 
gallery, communicating below with the ventral gallery, c. blind dorsal gallery. 
(| nat. size.) 
Fig. 27. P. sinuosum. Plan of ventral gallery and its lateral branches, d. a 
pocket-like diverticulum entering an incipient branch, aq. partly broken down 
aqueous tissue, (f nat. size.) 
Fig. 28. P. sinuosum. Median vertical longitudinal section of stem, (f nat. 
size.) 
Fig. 29. P. sinuosum. Vertical longitudinal section passing through two leaf- 
cushions. c. a blind dorsal gallery, (f nat. size.) 
Fig. 30. P. carnosum. Some of the old ground-tissue cells of the stem, to show 
band-like thickenings, (x 105.) 
Fig. 31. P. carnosum. Three cortical cells from a longitudinal section of a 
root, (x 190.) 
Fig. 32. P. carnosum. Microphotograph of a longitudinal section through base 
of petiole, showing its articulation with the leaf-cushion. 
PLATE XII. 
Fig- 33- P» carnosum . Transverse section of a stem-stele, e. outer endodermis. 
p. false pericycle or inner endodermis. s. sclerenchymatous sheath, (x 258.) 
Fig. 34. P. carnosum. Part of transverse section of root, (x 67.5.) 
Fig- 35- P. carnosum. Dorsal part of vascular cylinder, a. one of the foliar 
bundles leaving the edge of the foliar gap. b. small meshes separating two foliar 
gaps. c. place of origin of a lateral branch cylinder, d. a foliar gap. ( x 
about i|.) 
Fig. 36. P . sinuosum. Semi-diagrammatic drawing of a dissection showing 
the dorsal part of the vascular network, a. b. supposed limits of a foliar gap. 
(x about i|.) 
Fig- 3 7- P. carnosum. Part of a longitudinal section of a root, showing the 
collar (c ) formed by the ruptured epidermis of stem. Beneath this is seen the. 
piliferous layer of root, (x 75 -) 
Fig. 38. P. carnosum. Diagrammatic transverse section of petiole, a. inter- 
ruption of thick- walled hypoderma by the thin- walled spongy tissue. 
Fig. 39. P. carnosum. Diagrammatic section through a sorus-cup. 
Fig. 40. P. sinuosum. Diagrammatic section through a sorus. a. enlarged 
cells of epidermis at edge of pit. 
