326 MESSKS. HANCOCK AND ATTHEY 



ear-shaped. The stratum of granules follows the infoldings with 

 the greatest regularity. 



There is still another variety, which differs considerably from 

 all the rest. This is without tubes, the whole substance being 

 composed of large polygonal cells having the appearance of coarse 

 cellular tissue, with here and there a dark, irregular, spherical 

 body. 



Such are the variations in the structure of these Coal-Measure 

 fungi. They are, we have said, occasionally structureless, or 

 nearly so ; but this is rarely the case. We have sixteen speci- 

 mens that appear either homogeneous, or almost so, out of 

 one hundred and twenty-six sections, all the rest (one hundred 

 and ten) exhibiting more or less structure. This fact militates 

 strongly against the idea we at first entertained, that the tubu- 

 lar structure was a fungus parasitic in the bodies in which it is 

 found. Were such the case these figures ought to be reversed : 

 sixteen bodies so afi'ected might be found in one hundred and 

 twenty- six ; but certainly we should never expect to find out of 

 that number one hundred and ten affected and sixteen only free 

 from the parasite. 



The apparent entu'e homogeneity of some specimens, and the 

 apparent partial homogeniety of others, can be accounted for as 

 the result of fossilization. Fossil wood and other vegetable 

 substances have frequently the structure either wholly or par- 

 tially obliterated by pressure. This is not uncommonly the case 

 with wood found in the Newsham Coal-shale ; and it can scarcely 

 be doubted that such is the case with the fungi in question. We 

 presume that the general substance of these bodies is composed 

 of cellular tissue (and, indeed, in one of the varieties above men- 

 tioned we have seen that it is chiefly made up of cellular tissue, 

 and traces of such a structure have been observed in one or two 

 other instances), and that by pressure this is almost universally 

 obliterated. The ramifying tubes, with the spore-like bodies, 

 being of a less delicate nature, or in some way less perishable, 

 are sometimes preserved throughout the mass, at other times 

 only partially preserved ; occasionally the tubes are so strongly 

 defined, that every characteristic is retained ; again so delicate 



