^{page 33 note †} Trans. Roy. Soc. Edin., vol. xxxvii. p. 342, pl. iv. figs. 13–14, 1893Google Scholar.

^{page 33 note ‡} Trans. Roy. Soc. Edin., vol. xxxvii. p. 341, pl. ii. fig. 7Google Scholar; pl. iii. figs. 11–12, 1893.

^{page 33 note §} “Sur la classification des végétaux foss.,” p. 9, Mem. Muséum d'hist. nat., vol. viii. ParisGoogle Scholar.

^{page 33 note ∥} Archives du Museum, vol i. pp. 405–461Google Scholar, pls. xxv.-xxxv. (i.-xi.).

^{page 33 note ¶} Zeiller, , Ann. d. Sc. Nat. 6^e. sér., “Bot.,” vol. xix. p. 256Google Scholar, plates xi., xii., 1884; also in Flore foss. du Bassin houil. d. Valenciennes, p. 591, 1888.

^{page 34 note *} This specimen was named S. elegans by Brongniart in error. The fossil is his Sig. Menardi, Hist. d. végét. foss., pl. clviii. fig. 6 (? not fig. 5), which again is only a young condition of Sigillaria Brardii, Bgt., the type of the Clathraria section of Sigillaria. See Zeiller, , Ann. d. Scienc. Nat., 6^e. sér., “Bot.,” vol. xix. p. 259, 1884Google Scholar; Weiss, , Sitz-Bericht d. Gesell. natur. Frencole. Berlin, No. 5, 1886, p. 70Google Scholar.

^{page 35 note *} These, like those in ferns and lycopods, are not true vessels. They communicate with each other by lateral openings, and are not continuous as in true vessels, but the septæ forming the individual cells or utricules remain intact.

^{page 35 note †} Brongniart, Observations sur la Structure inter du S. elegans, p. 426.

^{page 36 note *} Witham, , “On the Lepidodendron Harcourtii,” Trans. Nat. Hist. Soc. Northumb., Durham, and Newcastle, vol. ii., read March 1832Google Scholar. Ibid., “Internal Structure of Fossil Vegetables found in the Carboniferous and Oolitic Deposits of Great Britain,” pp. 51 and 75, pl. xii. figs. 1–7, and pl. xiii., Edin., 1833. Lindley and Hutton, Lepidodendeon Harcourtii, Fossil Flora, vol. ii. p. 45, pls. xcviii. and xcix., 1833.

^{page 36 note †} Williamson, , “On the Light Thrown upon the Question of the Growth and Development of the Carboniferous Arborescent Lycopods by a Study of the Details of their Organisation,” Mem. and Proc. Manchester Lit. and Phil. Soc., 4th ser. vol. ix., session 1894–5, p. 47, 1895Google Scholar. See also Brongt., Hist, d. végét. foss., vol. ii. p. 37, pls. xx. and xxi., 1837; Bertrand, “Remarques sur le Lepidodendron Harcourtii de Witham,” Traraux et Mémoires des Facultés de Lille, vol. ii. Memoir No. 6, pls. i.-x. Lille, 1891.

^{page 37 note *} Mém. Presentes par divers savants a Baend. d. Science, vol. xxii. Paris, 1875. Plates. See also note on p. 62 of this communication.

^{page 38 note *} Note.—In the earlier part of this paper (p. 34) I have remarked that the Sigillaria degans, whose internal structure was described by Brongniart in 1839, was now recognised as his Sig. Menardi (in part), Hist. d. végét, foss., pl. clviii. fig. 6. This again is considered to be only a young condition of Sig. Brardii, Brongt., and to this last mentioned species the Sigillaria spinulosa, Germar, must be united as only representing a different state or condition of growth. See Weiss and Sterzel, Die Sigillarien der preussischen Steinkohlen-und Rothliegenden-Gebiete, II. “Die Gruppe der Sub-sigillarien,” Abhand der König Preuss. geol. Landesanstalt, Neue Folge, Heft. 2, Berlin, 1893, p. 84 et seq. Kidston “On Sigillaria Brardii, Brongt., and its Variations,” Proc. Roy. Phys. Soc. Edin., vol. xiii. p. 233, pl. vii., 1896. But there are great structural differences in the bark of the specimen described by Brongniart and that described by Renault and Grand 'Eury, differences which preclude the possibility of these two forms of cortex belonging to the same species.

Two questions therefore arise:—(First) Are the specimens figured by Renault and Grand 'Eury in their memoir on the internal structure of Sujillaria spinulosa, pl. i. figs. 2–3, really referable to that plant or one of the forms of Sig. Brardii? and (secondly) granted they do belong to this species, is it proved beyond doubt that the vascular axis described under the name of Sigillaria spinulosa really belongs to the bark found associated with it? From the crushed and broken condition of the axis and bark shown in their fig. 1, pl. i., the absolute proof that all these parts belong to the same stem appears to be wanting, and their relative position might be only accidental. These remarks are made from an examination of the figures and descriptions which accompany them only, as I have not had an opportunity of studying the original specimens.

^{page 38 note †} Comptes rendus, 7th Dec. 1885.

^{page 39 note *} See also in regard to the affinities of Sigillaria:—Renault, Cours d. botan. foss. Première Année, 1881, pp. 125, 151. Renault, “Structure comparée de quelques tiges de la flore carbonifère,” Nouvelles Archives du Muséum ds Paris, 2^e. sér., vol. ii. p. 213, 1879. Dawson, “On New Plants from the Erian and Carboniferous, and on the Characters and Affinities of Palæozoic Gymnosperms,” Peter Redpath Museum, McGill University, Montreal—Notes on Specimens, 1890, Canadian Record of Science, January 1890, p. 19 et seq.

^{page 39 note †} St Etienne, 1890, pp. 196–197.

^{page 39 note ‡} Grand 'Eury, loc. cit., p. 258.

^{page 40 note *} “On the Organisation of the Fossil Plants of the Goal Measures,” part x. p. 497, Phil. Trans., part ii., 1880.

^{page 40 note †} Loc. cit., Mem. x., pl. xiv. fig. 6.

^{page 40 note ‡} Williamson, “General Morphological and Histological Index to the Author's Collective Memoirs on the Fossil Plants of the Coal Measures,” part ii. p. 16, Mem. and Proc. M'ter. Liter. and Phil. Soc., session 1892–93, 1893. Note.—If the Halonial branch referred here to Lepidodendron Wunschianum belongs to this species, then the plant is a Lepidophloios. This does not, however, in the slightest alter the position of the question under discussion as to the occurrence of an exogenous zone in Lepidodendron, as it is present in Lepidodendron selaginoides and other species.

^{page 40 note §} Fossil Botany, English edit., p. 253, fig. 29, 1891Google Scholar.

^{page 41 note *} de Bart, A., Comparative Anatomy of the Vegetative Organs of the Phanerogams and Ferns, English edit., p. 623, 1884Google Scholar.

Note.—On the structure of Sigillavia and Lepidodendron the following additional works may be consulted:—H. Graf zu Solms-Laubach, Fossil Botany, being an Introduction to Palceophylology from the standpoint of the Botanist, English translation, Oxford, 1891. Sir Wm. Dawson, “On the Conditions of the Deposition of Coal, more especially Illustrated by the Coal Formation of Nova Scotia and New Brunswick,” Quart. Journ. Geol. Soc., May 1866, vol. xxii. p. 95. Ibid., Geological History of Plants, New York, 1888Google Scholar. Ibid., Acadian Geology, 2nd edit., London, 1868Google Scholar. SirHooker, W., “On the Vegetation of the Carboniferous Period, as Compared with that of the Present Day,” Mem. Geol. Survey of Great Britain, vol. ii. part ii. p. 387, 1848Google Scholar. Binney, , Quart. Journ. Geol. Soc., 1862, vol. xviii. p. 106CrossRefGoogle Scholar. Ibid., Phil. Trans., vol. clv. pp. 579 and 591, 1865Google Scholar. Ibid., Palwout. Soc., vol. xxix. pp. 97 and 147, 1875Google Scholar. van Tieghem, P., “Sur quelques points de l'anatomie des cryptogames vasculaires,” Bull. Soc. Bot. de Frann, vol. xxx. p. 169, 1883CrossRefGoogle Scholar. Ibid., Traité de Botanique, 1884. Williamson, Memoirs, “On the Organisation of the Fossil Plants of the Coal Measures,” in Phil. Transactions, No. ii. 1872; No. iii., 1872; No. ix., 1878; No. x., 1880; No. xi., 1881; No. xii., 1881; No. xvi., 1889. Ibid., “General, Morphological, and Histological Index to the Author's Collective Memoirs on the Fossil Plants of the Coal Measures,” part ii., Mem. and Proc. M'ter. Liter. and Phil. Soc., vol. vii., series 4, session 1892–93, 1893. Ibid., “On the Light thrown upon the Question of Growth and Development of the Carboniferous Arborescent Lepidodendra by a Study of the Details of their Organisation,” Mem. and Proc. M'ter. Liter. and Phil. Soc., session 1894–95, series 4, vol. ix., 1895.

^{page 42 note *} Traité d. paléont. végét., vol. ii. p. 105, pl. lxvii. figs. 12–24, 1870.

^{page 42 note †} Feistmantel, in 1876, under the name of Sigillariostrobus Goldenbergi, appears to include all the Sigillarian cones described by Goldenberg, but the accuracy of this course is open to serious doubt, l'ers. d. böhmischen Kohlen-Ablager, iii. Abth. p. 31, Cassel, 1876.

^{page 42 note ‡} Goldenberg, Flora Saræpont. foss., Heft. i. p. 25.

^{page 42 note §} Comptes comlus, 30th June 1884.

^{page 43 note *} “Cones de Fructification de Sigillaires,” Ann. d. Scienc. Nat, 6^e. sér., “Bot.,” vol. xix. pp. 256–280, pls. xi.-xii., 1884. See also Zeiller, Flore foss. Bassin houil. d. Valenciennes, pp. 591–608, pls. lxxxix.-xc., 1886 and 1888.

^{page 43 note †} Ann. d. Sc., loc. cit., pl. xi. figs. 1, 1a, 4, 4a, 4b.

^{page 43 note ‡} Loc. cit., pp. 264–265.

^{page 43 note §} Schimper, Traité d. paléont. végét, p. 105.

^{page 44 note *} Loc. cit., p. 267, pl. xii. figs. 1, 2, 2a.

^{page 44 note †} Études des Gites Mineraux de la France, Bassin houiller de Valenciennes. Flore fossile du Bassin houiller de Valeneiennes, Paris, plates i.-xciv., 1886, text, 1888.

^{page 44 note ‡} Ibid., p. 605, pl. lxxvii. figs. 2–3.

^{page 45 note *} See also Kidston, , “On Sigillaria Brardii, Brongt., and its Variations,” Proc. Roy. Phys. Soc., vol. xiii. p. 233Google Scholar.

^{page 45 note †} Flore foss. Bassin houil. d. Comentry, pp. 540–541.

^{page 45 note ‡} Phil. Trans., 1865, p. 595, fig. 6.

^{page 46 note *} Flore Carb, du Depart. de la Loire et du centre de la France, p. 160, pl. xiv. fig. 4, 1877.

^{page 46 note †} Ann. d. Sc. Nat., 6^e. sér., “Bot.,” vol. xix. p. 257Google Scholar.

^{page 46 note ‡} Loc. cit., p. 160, pl. xiv. fig. 5.

^{page 46 note §} Loc cit., pl. B fig. 13.

^{page 46 note ∥} Grand 'Eury, Geol. and Paléant. du Bassin houil. du Gard, 1890, pl. xiii. figs. 7, 8, 9, 10.

^{page 46 note ¶} Loc. cit., pl. x. fig. 6.

^{page 46 note **} See Zeiller, Flore foss. Bassin houil d. Valenciennes, pl. lxxviii. fig. 3 (Sig. lævigata). Ibid., pl. lxxxv. fig. 1 (S. tessellata).

^{page 47 note *} Die Calm Flora, Heft. ii. pl. xxv. figs. 2–3 (Sigillaria Eugenii, Stur).

^{page 47 note †} Wild, “On Section of Shaft sunk through the Middle Coal Measures at Bardsley Colliery, and an interesting Discovery of Calamites,” Manchester Geol. Soc., Feb. 2, 1886.

^{page 48 note *} Fossil Flora, vol. i. pl. xliii. figs. 1–2.

^{page 48 note †} Proc. Roy. Phys. Soc., vol. xii. p. 261Google Scholar, pl. vi, figs. 2, 2a, 1894.

^{page 48 note ‡} From the left bank of the Water of Leith, a little above Spylaw House, Colinton, Midlothian, Reg. Nos. 67 and 68.

^{page 49 note *} Geological Survey of Canada. Montreal, 1873, p. 41Google Scholar.

^{page 49 note †} Williamson, “On. the Organisation of the Fossil Plants of the Coal Measures,” part x., Phil. Trans., 1880, part ii. p. 494.

^{page 49 note ‡} Ante, p. 43.

^{page 50 note *} If I am correct in regarding the cause of these “roughnesses” to be contained microspores—pre sumably they were still united in groups of four, as is frequently seen in the cones of Lepidostrobus—then the size of the individual microspores would be less than 0·10, for the thickness of the containing envelope adds to their apparent size.

^{page 50 note †} The size of the microspores in a cone of Lepidostrobus showing structure is 0·02 mm.

^{page 53 note *} These macrospores have a great similarity to those figured in the Proc. Roy. Phys. Soc., vol. ix. p. 109, pl. iii. fig. 7Google Scholar (Triletes vii.), but it is improbable that they belong to the same species, as macrospores of different species have evidently a great similarity in form and structure, as seen in the case of those belonging to the two cones described in this paper.

^{page 53 note †} Binney, and Kidston, , Proc. Roy. Phys. Soc., vol. ix. p. 113Google Scholar, pl. v. figs. 16d and 16e, 1887.

^{page 53 note ‡} Zeiller, Ann. d. Scienc. Nat, 6^e. sér., “Bot.,” vol. xix. pp. 263 and 266, pl. xi. figs. 1 and 4, 1884; also Flore foss. Bassin houil, d. Valenciennes, p. 593, pl. lxxxix. figs. 2–3, 1886 and 1888.

^{page 55 note *} Coal Flora, pl. lxix. figs. 11–14.

^{page 55 note †} Flora Sarœ. foss., Heft. i. p. 25, 1855.

^{page 55 note ‡} Ibid., Heft ii. p. 1, 1857.

^{page 55 note §} Ann. d. Scienc. Nat., 6^e. sér., “Bot.,” vol. xix. p. 278, 1884Google Scholar.

^{page 56 note *} Trans. Roy. Soc. Edin., vol. xxxvii. p. 338Google Scholar, pl. iii. figs. 9–10, 1893.

^{page 56 note †} Lindley and Hutton, Fossil Flora, vol. i., pl. vii. fig. 1, pl. viii. ( = Lepidodeadron acerosum).

^{page 58 note *} As the leaf-cushions appear to become more distant with age, probably the younger conditions would represent true Clathraria.

^{page 59 note *} Weiss and Sterzel, Die Sigillarien d. preuss. Steink. n. Rothl., Gebiete, ii. “Die Gruppe der Sub-sigillarien,” p. 207, pl. xxvii. fig. 105, 1893, Abhandl. d. König. Prenss. geol. Landesanstalt, neue folge, Heft. ii. Berlin.

^{page 59 note †} Ibid., p. 209, pl. xxvii. fig. 106, 1893.