AN TJ.\DESCUIBi'',D FOSSIL I'llUlT. 587 



I'roui this triple composition or union of sporules, wiiicli 

 differs from the constant quadruple union in tribes of 

 existing plants, namely, Ophioglossece and Lycopodiacea, 

 which, from- other points of structure, may be supposed 

 most nearly related to the fossil, I have called it Triplo- 

 sporite, a name which expresses its fossil state, the class or 

 primary division to which it belongs, and its supposed pe- 

 culiarity of structure. 



The structure of the axis, which is well preserved in the 

 specimen, distinctly shows, in the arrangement of its im 

 vascular bundles, a preparation for the supply of an equal 

 number of bractese. These vascular fasciculi are nearly 

 equidistant in a tissue of moderately elongated cells. 



The vessels are exclusively scalariform, very closely re- 

 sembling those of the recent Ferns and Lyeopodiacece ; and 

 among fossils, those of Psarolites, Lepidodendron, and its 

 supposed fruit, Lepidostrobus, as well as several other 

 fossil genera; namely, Siyillaria, Stiymaria, Ulodendron, 

 Halonia ? and Diploxylon. 



The coat of the sporangium appears to be double ; the 

 outer layer being densely cellular and opake, the inner less 

 dense, of a lighter colour, and formed of cells but slightly 

 elongated. 



On the lower or adnate side of the sporangium this 

 inner layer seems to be continued, in some cases at least, 

 in irregular processes to a considerable depth. I cannot, 

 however, find that the sporules are actually formed in this 

 tissue, but in another of somewhat different appearance 

 and form, of which I have been only able to see the torn 

 remains. 



The minute granular bodies which accompany the 

 sporules in the drawing Tab. 35 (XXIV), fig. G, are pro- 

 bably particles of the mother cells, and are neither uniform 

 in size nor outline. 



The whole specimen has suffered considerable decay or 

 loss of substance, which is most obvious in the sporangia 

 fi-om their greater transparency, but equally exists in the 

 opake bractese, in which radiating crystallization occupies 

 the space of the removed cellular substance. 



