Mr. Brown on an undescribed Fossil Fruit. 471 



stinctly shows, in the arrangement of its vascular bundles, a preparation for 

 the supply of an equal number of bracteae. These vascular fasciculi are 

 nearly equidistant in a tissue of moderately elongated cells. 



The vessels are exclusively scalariform, very closely resembling those of the 

 recent Ferns and Lycopodiaceoe ; and among fossils, those of Psarolites, Lepi- 

 dodendron, and its supposed fruit, Lepidostrobus, as well as several other fossil 

 genera ; namely, Sigillaria, Stigmaria, 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 only been able to see the torn remains. 



The minute granular bodies which accompany the sporules in the drawing 

 Tab. XXIV. fig. G. are probably 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 from their greater transparency, but 

 equally exists in the opake bractese, in which radiating crystallization occut 

 pies the space of the removed cellular substance. , 



I cannot at present enter fully into the question of the afiinities of Triplo- 

 sporite. I may remark, however, that in its scalariform vessels it agrees with 

 all the fossil genera supposed to be Acotyledonous. In the structure of its 

 sporangia and sporules it approaches most nearly, among recent tribes, to 

 Lycopodiaceoe and Ophioglossece ; and among fossils, no doubt, to Lepidostro- 

 bus, and consequently to Lepidodendron. 



The stem structure of Lepidodendron, known to rae only in one species, 

 Lepidodendron Harcourtii, offers no objection to this view, the vascular ar- 

 rangement of the axis of its stem bearing a considerable resemblance to that 

 of Triplosporite. To the argument derived from an agreement in structure 

 between axis of stem and of strobilus I attach considerable importance, an 

 equal agreement existing both in recent and fossil Coniferce. 



VOL. XX. 3 Q 



