of the Fossil Plants of the genus Sigillaria. 123 
lines or bars, which, in general, are parallel to each other, but occasion- 
ally they divide, as is represented in fig. 5. All the tubes have their walls 
of a uniform thickness, so that Anabathra displays no appearance of the 
concentric rings which are found in the wood of ordinary exogenous 
trees. The ligneous zone appears to have been intersected by numer- 
ous narrow medullary rays, judging from the interspaces which are mark- 
ed d in figures 2 and 4. 
The vascular cylinder is composed of elongated tubes, which, on the 
transverse section, are irregularly angular, and somewhat variable in 
their proportion. Those of the greatest diameter are a little larger 
than the tubes composing the marginal strip of the ligneous zone, 
and they constitute the inner four-fifths of the cylinder; while the 
smallest, into which the others gradually pass, occupy the remaining 
or outer portion. At the margin of the cylinder, the vessels have be- 
come so diminished in size, as to resemble the small ligneous tubes 
which immediately circumscribe them ; occasionally a small vessel is 
to be seen among the larger ones. With the exception of their being 
placed somewhat according to size, as just stated, the tubes of the me- 
dullary sheath possess no order in their arrangement. The tissue of this 
part appears to be shorter than that of the ligneous zone, as there are 
several terminations displayed on a longitudinal section (vide , fig. 3) ; 
but I am strongly inclined to believe that the shortness is more apparent 
than real: it ought rather to be said, that the tubes, in their longitudinal 
direction, are very flexuous, and twisted around each other. This cireum- 
stance, by causing a longitudinal section to display certain of the tubes 
obliquely cut, and others deviating from each side of the plane of the 
section, it is conceived, would produce the appearance as if these cuts 
and deviations were so many terminations.* The walls of the tubes are 
marked with transverse lines or bars, which differ somewhat from those 
on the ligneous tissue, inasmuch as they are closer to each other, and 
they are often seen coming in contact, which gives them an anastomosed 
appearance (vide fig. 6, Plate IV.). In none of the large vascular tubes 
are the lines so disposed as to form a spiral, either broken or continu- 
ous: probably this is the case in the smallest but the section, is not suf- 
ficiently thin to allow of its being seen. The vascular cylinder is in close 
contact with the ligneous zone; and in no part does it display the least 
appearance of openings or medullary rays. 
The pith appears to have been composed of fusiform cells, analogous 
to those which Brongniart describes as belonging to the corresponding 
part of Lepidodendron. It may be doubted, however, that what I have 
considered as forming a portion of the pith of Anabathra, did, in reality, 
* May not the shortness of the vessels composing the medullary sheath and the 
leaf cords of Sigillaria elegans, be more apparent than real, and the appearance be 
produced as suggested in the text ? 
