OF THE BRITISH COAL MEASURES. 103 
Photographs 2-8. Heterangium tilicoides. 
Phot. 2. General transverse section, from specimen 1. Note the well-preserved cortex. 
T. 1. Double leaf-trace, in connection with stelar wood. 
T. 2. Next outer trace; only one bundle shown. 
T. 3. One pair of bundles of outermost trace. T. 3!. The other pair, damaged. 
X about 6. Slide, Manchester, R. 632. 
Phot. 3. General transverse section, from specimen 2. 
T. 1. Double trace, just leaving stele. 
T. 2. Bundles of a second trace, far out in pericycle. 
Lb., outer limit of large leaf-base in connection with stem. 
X about 6. Slide S. 237. 
Phot. 4. Leaf-base from Phot. 3, enlarged. 
v.b., one pair of bundles in the leaf-base ; v.5.', the other pair, damaged; C, outer cortex 
of leaf-base; se., sclerenchyma delimiting leaf-base laterally; p.c., portions of 
pericycle of stem. 
X about 11. Slide S. 237. 
Phot. 5. Part of another transverse section of specimen 2, showing a leaf-trace, consisting 
of two large bundles, starting from the stele. 
£., primary; x., secondary xylem of stele; ph.*, secondary phloem of leaf-trace ; 
p.c., pericycle. 
X about 40. Slide, Manchester, R. 654. 
Phot. 6, General transverse section from specimen 3. 
r.x., root-base, connected with the xylem of the stem; 7., free root. 
T. 2. Leaf-trace in pericycle. 
X about 6. Slide, Manchester, R. 658. 
Phot. 7. From the section next below the last. 
r., root, imbedded in the cortex of the stem. 
X about & Slide, Manchester, Q. 60. 
Phot. 8. Genera] transverse section from specimen 4. Note that everything beyond the 
pericycle is lost. 
T. 1. Inner trace, of two bundles, just leaving the stele. : 
T. 2. Outer trace, of two widely separated bundles, passing out from the pericycle. 
Cf. Pl. 4. fig. 19. 
X about 6. Slide S. 1323. 
PLATE 2. 
Photographs 9-15. Heterangium Lomaxii. 
Phot. 9, Form 8. General transverse section from specimen 1. Lowest section. 
v.b., the two widely separated bundles of the leaf-trace. 
x 6}. Slide S. 447. 
Phot. 10. Peripheral xylem-strands from Phot. 9, enlarged. 
px., protoxylem of one of the strands; x., primary; 4.7, secondary xylem. 
X about 40. Slide S. 447. 
Phot. 11. Form B. General transverse section from specimen 1, Uppermost section. 
v.b., the two bundles of the leaf-trace, here much more widely separated than iv 
Phot. 9; r., adventitious root passing out between them. 
x about 8, Slide W. 1915 A. 
