Benson.—Mazocarpon or the Structural Sigillariostrohus. 583 
text-book ‘Elements de Paleobotanique’, Fig. 138, are shown as little 
groups on each cone-scale, which certainly suggest a maximum of eight per 
sporange, but in an incrustation the sporange-wall has naturally perished, so 
that we can lay no stress on this specimen. 
The fragile nature of the sporange-wall has prevented it being demon¬ 
strated in any of Zeiller’s and Kidston’s specimens, while in Mazocarpon no 
single radial section shows the wall unbroken ; the sporange in Text-fig. 2 
shows only vestiges of the wall. 
The sporange in Fig. 18 is the most complete on the cone in S. Cn. 
1 595 - 7 ’ an d the wall can be seen to be broken in two places. All the 
sporangia in the cone are mature, but owing to the broken condition of the 
sporange-wall it is often difficult to be clear as to the limits of the respective 
sporangia. This is the usual condition in Sigillariostrohus and led one 
observer 1 to suggest that the spores were formed in the bract without 
a sporangial wall. 
2. The Cones. 
The characters of agreement between the structural specimens of the 
cone and the incrustation specimens of the cone of Sigillariostrohus both in 
Zeiller’s and Kidston’s material extend to the following : 
a. Dimensions. 
b. Phyllotaxy. 
c. Form of bract. 
d. Pedunculate character of the cone. 
e. Agreement between the hexagonal form of section of cone-axis and 
the dimensions and form of the scar in the incrustations of 
Sigillaria mamillaris . 
f. Cone-scale scar on the cone-axis. 
g. Caducous nature of the cone-scales. 
a. Dimensions . In Part I, p. 575, we estimated the cone in 5279 1-9, to 
be between three and four inches in length and a little over 13 mm. or half 
an inch in diameter. If these measurements are compared with Kidston’s 
figures 2 of Sigillariostrohus rhomhibracteatus , Plate I, Fig. 3, and Plate II, 
Fig. 10, they will be seen to correspond very closely with the dimensions 
of that species. 
We cannot of course expect to determine the length of the peduncle, 
nor is there any reason to consider that all Sigillaria cones were of the 
same size, but the general agreement indicated above in the dimensions of 
the available material is sufficiently striking. 
b. Phyllotaxy . Both show a close spiral phyllotaxy. 
c. Form of bract. The description given in Part I, Section V, not 
1 Kidston : ‘ Les Vegetaux houillers recueillis dans le Hainault Beige,’ 1911, p. 184, Fig. 32, 
2 Kidston, loc. cit. 
