BE fig. 
q. 1, 
16 2 
I 3. 
I 4, 
1g 5 
Il. 6 
IL 7 
II. 8 
Il. 9 
il. 10. 
oe - il 
Mm 12 
m 613 
I 14, 
i «= 15. 
om @6«=—«éd‘«’. 
mm. 17. 
am 6«(18. 
Il. 19. 
foe §8=s 20. 
THE INTERNAL STRUCTURE OF SIGILLARIA ELEGANS. 549 
EXPLANATION OF PLATES I-III. 
Sigillaria elegans, Brongt. (Sternb., sp.). 
Portion of outer surface of the specimen from near Huddersfield. Halifax Hard bed, Lower 
Coal Measures. Natural size. To the right is seen a row of leaf scars. Specimen No. 
3497. 
Part of the same specimen enlarged two times. To the right is seen the vertical row of leaf 
scars, and to the left the surface of the cortical layer which bears the leaf cushions. 
Transverse section of the vascular cylinder and part of the cortex x 44. Primary xylem, ~.' 
Secondary xylem, 2.” Leaf cushions, J.c. and /.c.’ Slide No. 964. 
Portion of vascular cylinder x 35. Protoxylem, prx. Primary xylem, x.’ Secondary xylem, 
x.” Pith-cavity, p.c. Slide No. 964. 
Longitudinal (radial) section of leaf cushions x 20. Spongy transparent parenchymatous 
tissue, p. Dense tissue of smaller cells, p.p. Leaf trace opening, /.t. Very dense tissue 
at upper left corner of figure, periderm. Slide No. 841. 
Radial section passing through xylem x 95. Protoxylem, prx. Primary xylem, x.’ Secondary 
xylem, w.” Slide No. 967. 
Radial section passing through xylem x 170, At pra. is shown the termination of a tracheide 
belonging to the protoxylem. Slide No. 967. 
Radial section passing through xylem x 95. Protoxylem, pra. Primary xylem, x.’ Secondary 
xylem, 2.” Slide No. 968. 
Radial section passing through primary xylem x 95, At.’ is shown the termination of a 
tracheide. Slide No. 970. 
Transverse section of secondary xylem x 95. Showing medullary rays, mr. Slide No. 964, 
Transverse section showing leaf trace x 85. Protoxylem, prx. Primary xylem, x.’ Leaf 
trace, l.t., which is about to become free from the metaxylem. Slide No. 961. 
Transverse section showing leaf trace x 85. Lettering as before. The leaf trace has just 
become free from the metaxylem. Slide No. 966. 
Transverse section of leaf trace x 85. Lettering as before. The leaf trace has moved 
outwards and is becoming suddenly bent to pass out through a medullary ray. Slide No. 
964. 
Transverse section of secondary xylem, showing cells of medullary ray with spiral thickening 
mr. x 115, Slide No. 962. 
Transverse section showing leaf trace at outer margin of secondary xylem x85. Medullary 
ray, m.r. Secondary xylem, x”. Leaf trace, /.4. The leaf trace has bent upwards after 
emerging from the secondary xylem, and is cut through at approximately right angle. 
Slide No. 962. 
Transverse section of leaf trace quite free from the outer margin of the secondary xylem x 85. 
Slide No. 962. 
Transverse section of xylem x 95. Primary xylem, 2.’ Secondary xylem, «.” At .t, is seen 
the narrow spread-out base of the leaf trace shortly before it dies out. Slide No. 964. 
Outer surface of a specimen showing the leaf scars and portion of a circle of cone scars, c.s. 
Natural size. From Wombwell Main Colliery, near Barnsley, Yorkshire. Horizon, 
Barnsley Thick Coal, Middle Coal Measures, Collected by Mr W. Hemingway. 
Specimen No. 989. 
Radial (longitudinal) section passing through six leaf cushions x 4. Periderm, yp.d. 
Surface to which leaf was attached, s.a. Opening through which leaf trace passed, J.t. 
The cushion marked /.t. is enlarged at fig. 5. Slide No. 841. 
Transverse section of cushion x 14. ‘Transparent parenchymatous tissue, p. Broken down 
margin of cushion, pp. Periderm, pd., pd.’ The part marked pd.’ is enlarged at fig. 21. 
Slide No. 962. 
TRANS. ROY. SOC. EDIN., VOL. XLI. PART III. (NO. 23). 82 
