OF THE FOSSIL PLANTS OF THE COAL-MEASURES. 
347 
Fig. 76a represents a somewhat similar conceptacle, but in this instance the outer 
wall of the organism consists of a single layer of cells, a, the flattened inner ends of 
which form the boundary of the conceptacular cavity. The dark ring in the figure 
merely represents part of this surface of the inner cavity which has not been crossed 
by the section at its greatest diameter, and which is consequently seen a little out of 
focus. This example differs from the figs. 75, in the fact that in the former the outer 
extremities of the cells bear no appearance of having been forcibly detached from some 
other surrounding parenchyma, and only consists of a single row of elongated cells 
disposed vertically upon the cavity which they invest. This specimen, which is from 
one of Mr. Finn’s Halifax sections, has a maximum diameter of ‘0166. In its interior 
is what appears to be a collapsed, structureless membrane, c, that originally lined 
the cavity. 
I have not yet obtained the slightest clue to the plants to which these curious 
objects belong ; but some of them inevitably remind the botanist of the spore cavities 
seen in sections of the fertile frond of Ophioglossum vulgare. 
Fig. 77 represents two detached microspores and one united cluster of four, but of 
which only three can be seen in any one position. These, which are from a fragment 
of a Halifax strobilus, are introduced to serve as standards of comparison in reference 
to the other structures just described. They are enlarged, like the figs. 63-73, 74, 
and 76, 214 diameters. 
Both Mr. Binns, Mr. Spencer, and Mr. Earnshaw have supplied me with 
examples of the very remarkable objects represented in figs. 67, 68 and 69. Fig. 67 
represents a section enlarged 50 diameters, its actual breadth being - 025. Its outer 
wall, exclusive of its projecting hairs, is about ‘0023 in thickness. Fig. 68 represents 
a segment of the circle enlarged 214 times. The wall appears to consist of a row of 
cells, fig. 68, a. a, shaped like dumb-bells, arranged perpendicularly to the surface 
of the organism. At the outer and inner surfaces of the structure the enlarged 
extremities of these cells are in unbroken contact, looking like two layers of ordinary 
tabular parenchyma ; but the middle constricted portions of the cells appear to stand 
isolated, and to be surrounded by a continuous cavity, fig. 68, b, like a chamber whose 
roof and floor are connected by a series of pillars with bases and capitols. Supposing 
it possible that the lozenge-shaped spaces, fig. 68, b, might be occupied by a central 
series of cells, I examined the specimens carefully in search of a double cell-wall ; but 
having failed to find anything of the kind, I consider that these are what I have 
already suggested, viz., a continuous network of inter-cellular spaces traversed vertically 
by the constricted parts of the cells, and shut in by the continuous outer and inner 
surfaces of the organism. The specimen just described is from Mr. Spencer’s cabinet. 
Fig. 69 represents part of a second specimen sent to me by Mr. Binns. It is obviously 
obtained more recently exbibit tbe same arrangement. I propose grouping these and some allied objects 
in a provisional genus Sporocarpon, and the present species may be designated Sporocarpon cellulosum. 
June 10th, 1878. 
