SIGILLARIA VASCULARIS. 



141 



§ 3. The Specimen No. 44, Sigillaria vascularis, Binney. Plate XXII, 

 figs. 1—4, and Plate XXIII, figs. 1—3. 



Specimen No. 44, fig. 1 (natural size), is the outside of a calcareous nodule from the 

 Bullion Seam " of coal at Clough Head, near Burnley, showing the transverse section 

 ■of a root, in a most beautiful state of preservation. Every part of the central axis (com- 

 posed of large and small tubes and cells, barred on all their sides, and arranged v^^ithout 

 order) is entirely preserved in its structure, as is also the woody cylinder surrounding it ; 

 about one half of its diameter arranged in radiating series, with no division in its wedges, 

 and separated from the axis by a sharp and distinct line. No oval openings are seen in 

 the thin end of the wedges, like those of the Stigmaria (No. 41) hereinbefore described. 

 On the outside of the woody cylinder is a zone of lax parenchymatous tissue, much 

 disarranged, but gradually passing into an outer radiating cylinder of prosenchymatous 

 tissue, which is traversed by numerous bell-shaped cavities, that contain the vascular 

 bundles leading to the rootlets. In fact, we have a Stigmaria showing a medulla, or 

 ■central axis, surrounded by a woody cylinder, but separated from it by a distinct line of 

 demarcation, and having none of the openings communicating with the central axis such 

 as are met with in Stigmaria like No. 41. The scars, in the form of depressed areolae, 

 •on the outside, are not shown, being enveloped in the matrix of carbonate of lime ; but 

 the bell-shaped cavities are well exhibited, and sufficient to prove it to be a Stigmaria, and 

 in all respects similar in structure to the specimen of Sigillaria vascularis, Nos. 39 and 40, 

 hereinbefore described. 



Pig. 2 (magnified 6 diameters) is a representation of the central axis and the inner 

 ■radiating cylinder ; the former composed of large and small tubes and cells, barred on all 

 their sides ; the latter being found chiefly near the centre, and the outside next to the 

 "woody cylinder. The last-named part is composed of rectangular tubes, placed close 

 together, increasing in size as they extend outwards, and in radiating series. This figure 

 is taken by reflected light. 



Pig. 3 (magnified 15 diameters) is a transverse section of another portion of the 

 inner radiating cylinder, composed of rectangular tubes, showing a large vascular bundle 

 and a small medullary ray. 



Pig. 4 (magnified 12 diameters) is a tangential section of the inner radiating cylinder 

 of barred tubes, showing a large oval vascular bundle of about thirty cells^ (r/), and smaller 

 medullary rays of one and two cells each {d'), arranged in vertical series. 



Plate XXIIl, fig. 1 (magnified 8 diameters), is another transverse section of the same 

 specimen, in a different part of the root, and seen by transmitted light, showing the 

 central axis and the inner radiating cylinder, as previously described. It is given for the 



1 In the figure only six cells are shown, but more than thirty are seen by a high power. 



