Benson.—Mazoccirpon or the Structural Sigillariostrohus. 577 
hollow of the sporophyll below in which the sporangial lamella lay, rupture 
of the sporange and its attachments would necessarily ensue. It has already 
been pointed out that these were quite unusually fragile. 
Section VI. The Microsporange. 
In June, 1913, a series of four tangential sections from a microsporange 
on a bract, but separate from the cone-axis, was secured from a Shore coal 
ball (H. Cn. 526, 12-15). 
That in 526, 12, is proximal and is injured at the point of attachment 
to the bract, but shows the tetrads well (Fig. 11). 
That in 526, 13, is the most perfect of the series (see Fig. 12). 
That in 526, 14, is injured very slightly on the dorsal ridge of the 
sporange, but shows the position in the pedicel of the vascular bundle. On 
the left is seen a lateral lamella (Fig. 13). 
That in 526, 15, is cut 
through the wedge - shaped 
sterile distal part of the spor¬ 
ange beyond the attachment to 
the bract, which is also cut 
through (see Text-fig. 3). 
Though unattached, the 
body is identified as Mazo - 
carpon by its structure through¬ 
out, and especially its lateral 
lamella, which is so thin at the 
margin that it is turned back 
on itself. The tissue, which 
seems to correspond with the 
tapetal tabular cells of the megasporange, is here divided up into series 
of short cells. 
The spores are formed not merely in one uniform layer over a sub- 
archesporial pad, but in several supplementary masses, with sterile tissue 
between them, so that the sporange bears some resemblance to the micro¬ 
sporange of Isoetes. The structure suggests that parenchyma has been 
formed from potential sporogenous tissue. The spores are still arranged in 
tetrads, as is so frequently the case in Lepidostrobus. They measure 55 /i by 
65 [x and are thus larger than those of Lepidostrobus and smaller than those 
of Spencerites . 
There is nothing to indicate how the sporophyll was borne, but 526, 11, 
has a part of a megasporange and megaspores occurring in the same section 
as the microsporange. This, however, is not surprising, as the sections are 
rich with Sigillaria leaves, so that if it can be shown (see Part II) that 
Mazoccirpon is Sigillariostrobus it would be quite consistent for both kinds 
Text-fig. 3. Mazoccirpon microsporange. A 
vertical section through the distal part of the sporange- 
vvall where it is free from the bract. H. Cn. 526, 15. 
