OF THE FOSSIL PLANTS OF THE COAL-MEASURES. 
343 
whatever direction they are intersected. In this respect they remind us of the 
supposed fruits of Aster ophyllites, as represented by my Volkmannia Dawsoni* rather 
than of true Lepidodendroid structures. But the spiral arrangements of the strobilus 
under consideration, and the verticillate ones of the Volkmannia, place them widely 
apart. 
Several important questions arise out of the study of this fruit, but which mainly 
centre in one, viz. , what are these tetraspores ? 
On first examining these specimens, I was inclined to believe that the triquetrous 
body, a, was a large microspore, and that the enclosed spherical objects seen in 
figs. 42, 43, and 44, f were identical with those figured by Hofmeister in plate lvii., 
figs. 13, 14, and 15, of the Bay Society’s edition of his ‘ Higher Cryptogamia.’ 
But two reasons militated against this conclusion, 1st, the large size of the spore- 
like bodies, a, and 2nd, their invariable adhesion to greater or smaller portions of 
cellular tissue, whereas developed microspores are invariably free. To illustrate the 
question of size I have, in figs. 48, 49, 50, and 51, drawn some true microspores to the 
same scale, i. e. , enlarged 100 times. Fig. 48 represents three detached microspores 
from the crushed Lepidostrohus supplied to me by Mr. Binns, and fig. 77 three others, 
all from the same bed near Halifax as the specimens under consideration. Figs. 49 
and 50 represent two clusters, each consisting of four microspores (only three being 
visible), from two Oldham examples of Lepidostrohus. Fig. 51 represents a similar 
cluster from a sporangium of the recent Lycopodium alpinum. It will at once be seen 
that the size of each of these small microspores differs so widely from that of the large 
bodies under consideration as to make it most improbable that the latter can also be 
microspores. Three other possibilities remain — 1st. they are macrospores ; 2nd, they 
are the mother-cells of microspores, the granules,/’ seen in figs. 42, 43, and 44, being 
the true microspores in an early state of development ; 3rd, they are spores of a special 
kind, belonging to a strobilus of the type of the recent Lycopodium, and which 
only possessed one kind of spore. The latter appears to me to be the more probable 
explanation of their nature, though the second supposition is not an impossible one, 
nor without its illustration amongst living Lycopods. Thus in plate lvii., fig. 10, 
Hofmeister figures the mother-cells of the microspores of Selaginella Martensii, 
which are arranged in such a manner as to give each cell one rounded side and three 
flat ones, terminating at a projecting angle. This is exactly the form of my examples. 
Whenever I obtain the specimens attached to then* surrounding cells, I invariably 
find that each of the spore-shaped bodies, a, rests upon those cells by its larger 
concave surface, whilst its other three sides stand up in bold relief, the conical apex, 
being uppermost and wholly free, as in figs. 44, 45, and 46. Fig. 57 demonstrates 
that four of these bodies were primarily in juxtaposition, as the common products 
ol one large fertile parent cell, and that the surrounding cells, d and g, seen in fig. 46, 
were barren cells belonging to the same cluster as each of those fertile parent cells. 
* Part V., Plate 5, fig. 28. 
2 Y 
MDCCCLXXVIII. 
