488 MISS T. L. PRANKERD ON THE STRUCTURE OF 
16. Омуви, F. W., 1903 on, the Structure of the Paleozoic тее 
and Scorr. рН" vagenostoma Ботан. 11. Trans. Roy. 
у Нос. В. vol. 197. р. 193. 
17. Scorr, D. H., 1900.—Studies in Fossil Botany, А. & С. Black. 
18. Storrs, М. C. C., 1905.—On the double Nature of the Cycadean Integu- 
ment. Annals of Botany, xix. p. 261. 
19. WIELAND, G. R., 1911.—A Study of some American Fossil Cycads : 
Pt. V. American Journ, Sci. vol. xxxii. 
20. WirnLIAMsON, W. C., 1877.—On the Organization of the Fossil Plants of 
the Coal Measures: Pt. VIIT. Phil. Trans. Roy. Soc. vol. 107. p. 232. 
21. —  1879.— Ditto : Pt. X. Ин. vol. 171. p. 517. 
EXPLANATION OF THE PLATES. 
b. — blister. | o.s. = outer shell. 
c.p. = central papilla. р. = prothallus. 
c.c. = central cone. pc. = pollen-chamber, 
ch.pl. = chalazal plate. p.gr. = pollen-grain. 
е. = epidermis. pl. = plinth. 
Jf. = fibrous layer. r. = ridge. 
Л. = fluted lining of canopy. sp. = spore. 
g. = germinal tube. s, = septum. 
yr. = groove. sí, = sinus. 
1. = loculus. s.s, = secretory вас. 
lac. = lagenostome wall. s.t. = soft tissue. 
т. = megaspore membrane, stp. — stopper. 
п. = nucellar membrane. v.b. = vascular bundle. 
т. = micropyle. 
PLATE 22. 
Fig. 1. а and b cells from the fibrous layer of В. 20а (1). «illustrates the way the 
* contents " of b are derived. C7. p. 469. c— cells from the fibrous layer of К. 21, 
a showing special type of preservation. х 560. . 
Fig. 2. Part of the wall of the seed of fig. 27 enlarged. The position of the portion drawn 
is indicated by the reference lines e. and v.b. Note the differentiation of the cells 
of the fibrous layer occurring opposite the bundle, which is torn away. В. 22. 
x 300. 
Fig. 3. Portion of epidermis in surface view to show appearance ‘suggestive of original 
continuity of protoplasts, В. 26 (fig. 12). x 360. 
Fig. 4. Part of vascular bundle cut longitudinally about half-way up the seed (cf. p. 474). 
R. 48 (1). x 360. 
Fig. б. Two pollen-grains and a body of unknown origin from the pollen-chamber of К. 38. 
x 168. Cf. р. 478. 
Fig. 6. Two secretory sacs from the base of К. 41 (2). x 360, 
Fig. 7. Fungal spore (or vesicle) occurring in the crushed seed in В. 46. x 770. 
Fig. 8. Another type of fungal spore from В. 52. x 770. 
