296 
PROFESSOR W. C. WILLIAMSON ON THE ORGANIZATION 
of the bracts. In every instance they have been too much disorganized to display their 
true contours ; but both figures 23 & 24, Plate XLIV., show that they are prolonged so 
as to form a thin investment to the exterior of the strobilus. 
The sporangia of the upper part of this fruit are densely filled with innumerable 
microspores, whose mean diameter is about ‘0007. Sometimes they are tetrapartite 
(Plate XLV. fig. 26, w ), and at others tripartite (fig. 26, w'). In the lower part of the 
strobilus the sporangia are occupied by the remarkable macrospores represented in 
Plate XLIV. fig. 27, x *. These vary considerably in their form, owing to pressure or 
shrivelling ; but they appear to have been more or less spherical. The one figured, 
the length of which exceeds its breadth, has a longer diameter of about *027 ; and 
from this to *05 appears to have been nearly the average size of these objects. The 
characteristic peculiarity of these macrospores is the projection from every part of their 
external surfaces of numerous caudate appendages, and which appear to be actual pro- 
longations of the investing layer of the spore. These appendages vary in length from 
*003 to ’0055, whilst their diameter is about ‘0006. They are rather thicker at their 
bases than nearer their extremities ; but the extreme tip of each one is slightly capitate. 
They have evidently been very flexible, since they are twisted into varied positions. I 
detect in them nothing resembling elaters, their texture, like that of the external spore- 
wall, being perfectly homogeneous. When the strobilus is viewed either by transmitted 
or by reflected light, all the spores, whether large or small, appear of a rich brown colour, 
a condition which has been noticed by Mr. Binney and Professor Morris as characterizing 
certain spores which have come under their ob servation f. I have not succeeded in dis- 
covering any structure in the interior of these objects. I have only obtained these macro- 
spores in actual connexion with two strobili. In one they occupy the lower part of the 
fruit as already described, four sporangia of which fruit are represented in Plate XLIV. 
fig. 28. It will be seen from the latter figure that most of these spores (x) are torn and 
distorted. In another fruit the numerous shrivelled sporangia remain ; but they have all 
shed their macrospores, with the exception of three, the spores of which closely resemble 
those shown in fig. 28. In all these examples the rich brown colour resides in the 
spore-wall, and not in its contents, whatever those may have been. 
That we have in this fruit a new example of that remarkable class of fossil strobili 
to which attention was first called by Bobert Brown and Professor Brongniart is 
obvious; and I think the reasons I have already given justify me in connecting it with 
the stems and branches with which I find it associated. No plant of the Lepidodendroid 
family occurs in the deposit other than those which I have described, save one or two small 
fragments of a Lepidodendroid bark of the ordinary type, and which very possibly belong 
to the lowermost parts of the stems now described. In many recent Cycads we find that, 
immediately below the cluster of perfect leaves, we have a considerable part of the stem 
* In this figure the macrospore (a?) and the microspores (tv) are drawn to the same scale, showing their 
relative sizes. 
t Binney’s “ Observations on the Structure of Fossil Plants, &c.,” part ii. pp. 44 & 45. 
