450 CASH: FOSSIL FRUCTIFICATIONS OF YORKSHIRE COAL MEASURES. 
Each sporangiophore stands out at right angles to the axis of the 
fruit spike, and is enlarged at its outer extremity into a considerably 
thickened peltate disc. 
The aporangia or spore sacs are attached to the inner surface of 
each peltate disc, usually in fours, arranged around its pedicel. 
The spores which show no trace of the presence of elaters fill 
the sporangia and are of small size, ranging in diameter from 04 
to "05 m.m. in diameter. 
The axis of the fruit spike is provided with a solid medulla, 
composed of parenchyma, the cells of which are somewhat elongated 
vertically, and which is enclosed in a thin cylinder of barred spiral 
vessels. 
Professor Williamson in his memoir on the organisation of the 
Fossil plants of the coal-measure, read 17 June, 1880, was enabled 
from a specimen supplied to him from my cabinet to clear up an 
uncertainty as to the position of the organic union of the sporangia 
to the sporangiaphores. 
The disc in this specimen consists of a mass of parenchyma, 
amongst the cells of which an extension of the bundle of spiral cells 
that passes along the peduncle of the sporangiophore, is prolonged 
towards the margin of the disc ; as the bundle approaches this margin 
its cells multiply as is the case with similar structures in the 
sporangiophores of recent Equisetum, as well as in other very different 
structures, e.g. the terminations of the hair-like emergences of the 
Drosera. The peripheral surface of the disc appears to have been 
composed of a layer of oblong cells, which are planted perpendicularly 
to it. Each sporangium is not connected with the peltate end of the 
sporangiophore by the entire base of the former, as is the case 
in the living equiseta, but a very narrow neck of cellular tissue 
attached to a point a little within the extreme overhanging margin 
of the sporangiophore; the remainder of the sporangium being 
entirely free. 
I have specimens of Calamostachjs Binneyana in my cabinet 
from the Halifax Hard Bed, Lower Coal Measures, of Sunny Bank 
and Bank Top Pits, Southowram, of Sugden Pit, near Halifax; 
