OF THE FOSSIL PLANTS OF THE COAL-MEASURES. 539 
of the prosenchymatous tissues of the bracts or sporangiophores ol the 
cone. 
Fig. 83. Superficial aspect of the cells of the sporangium-wall. 
Fig. 84. Vertical section of a portion of a sporangium-wall. 
Fig. 85. A sporange, a, a", containing three Traquarice, two of which are intersected 
equatorially, and the smaller one tangentially. Enlarged 16 diameters. 
a . Fragments of two other sporangia. 
Fig. 86. Portion of a tangential section of one of the Traquarian macrospores of 
the strobilus. Enlarged 225 diameters, a. Inner structureless layer of 
the exosporium. b, d. Transversely intersected bases of 11 of the 
radiating tubular spines, c. Long radiating tubes given off* from the 
base of each spine. 
Fig. 87. Portion of a transverse section of the outer or tubular layer of the exosporium 
of a macrospore. Enlarged 640 diameters, b, b', b'". The basal portions 
of three radiating tubular spines, with their lateral branches, c. Large 
basal tubular branch of the spine, b, corresponding to c, c, of fig. 86 . c! . A 
similar tube of the spine, b', b". d. Secondary tufts composed of diclio- 
tomously branching tubes, e, e. Secondary tubular branches of the 
upper portions of the primary spines. 
Fig. 88. Portion of the contents of the endosporium of fig. 87. Enlarged 320 
diameters, a. Portion of the endosporial membrane, b. Large thin- 
walled cells, c. Smaller dark-coloured cells. 
Fig. 89. Transverse section of a specimen of Sporocarpon asteroides. Enlarged 18 
diameters, a. Inner free membranous capsule, b. Condensed central 
substance. 
Fig. 90. Transverse section of a petiole of Rachiopteris di-upsilon. Enlarged nearly 
6 diameters, a, a. Vascular axis. b. Thin layer of small parenchy¬ 
matous cells, c, c. A pair of vascular foliar (?) bundles, d, d. A second, 
yet more external pair of similar bundles, f. An undivided symmetrical 
bundle, apparently similar to c and d. h. Coarse, large-celled parenchyma 
in vertical columns. 
Fig. 91. Vertical section across the middle of the central vascular bundle, a, of 
fig. 90. Enlarged 55 diameters, a. Scalariform vessels, b, b. Thin 
investment of narrow, oblong cells. 
