FROM THE LOWER COAL-MEASURES. 67 
EXPLANATION OF THE PLATES. 
Plates 7-9, photographs by Mr. L. A. Boodle, F.L.S. 
Figs. 1-5 (Pl. 7) and fig. 6 (Pl. 8) are selected from the series of transverse sections, numbered from 
below upwards (see table on pp. 46-47). 
PLATE 7. 
Fig. 1. Stele and surrounding tissues from Section IIT. The stele is surrounded by meristeles of 
various dimensions. a, 8, future meristeles, which at this level are still in connection with 
the stele; 88, a minor meristele, just detached from 8; y, meristele which subsequently 
fuses with 8 ; 6, another meristele (see Pl. 10. fig. 19) ; m, small meristele which subsequently 
divides up into bundles (see Pl. 8. fig. 7). x nearly 11. 
Fig. 2. From Section V. (Prof. Oliver's, O. 35). 8’, meristele detached from 8, which is just 
becoming free; m.b., three bundles derived from the meristele m.; other lettering as before. 
x nearly 11. í 
Fig. 3. From Section VIII. a shows signs of separation from the stele and division into two; 
8 and 8’ quite free; y has given off bundles above and below; m.b., bundles more widely 
separated (see Pl. 8. fig. 8). x nearly 11. 
Fig. 4. From Section IX. (Miss Stopes's). « is now free and a’ is detached from it; /9 is fusing 
with y. x nearly 141. 
J. From Section X. (Prof. Weiss’s). Complete transverse section, including the cortex and 
leaf-bases. 2! has here divided into two; B, the fused meristele composed of 8 and y; 
B', small meristele detached from B; d.r., d.r.', double rows of leaf-trace bundles, referred 
to in text (p. 49) ; v.b., two foliar bundles fusing. x nearly 14. 
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PLATE 8. 
Fig. 6. From Section XVII. (uppermost of series). Parts of the cortex and leaf-bases are included. 
a is here beginning to divide into two; B is giving off another bundle on the right; 
d.r., d.r./, the double rows of bundles, which here appear to mark the limits of a leaf-base. 
x nearly 14. 
a-region of stele from Section II., enlarged; aa, portion of æ about to become detached; 
m., small meristele, which divides up at a higher level; b., bundle probably derived from m. 
x about 4. 
Fig. 8. a-region from Section VHI., enlarged.  p.z., protoxylem-group on inner surface of a; 
m.b., three bundles derived from the division of the meristele; 5., bundle previously free. 
x about 4. 
Fig. 9. B-region of stele from Section IX., enlarged, showing the fusion of 8 with y. y', bundle 
previously derived from y; ĝ', part of 9 previously detached. x about 4. 
Fig. 10. Portion from outer part of stele, to show secondary growth beginning. æ, primary wood; 
pæ. protoxylem-group; 4?, secondary wood; cò., cambium; ph, secondary phloem, 
Section IV. x 55. 
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PLATE 9. 
Fig. 11. Portion from exterior of stele, to show protoxylem. pæ., two protoxylem-groups. The 
tracheides and parenchyma of the primary wood are seen to the interior. Section I. 
(Mr. Watson's). x about 30, 
Fig.12. Longitudinal section from primary wood of stele, to show elongated forms of bibis, 
differing from that in Megalozylon. Section M. x about 4. 
