The conidia of this form were found to be fairly abundant in the silicified tissue investigated by Felix; they occur usually in chains of 2 to 6 conidia having an ovoid or flask-shaped form, with a thick membrane (fig. 43, 4). The mycelium consists of branched hyphae divided into long cylindrical cells by transverse septa; occasional instances were found of an H-shaped fusion between lateral branches of parallel hyphae. Felix compares this species with examples of the genera _Haptographium_ and _Dematium_ of the family Sphaeriaceae; it was found in the woody tissue of a dicotyledonous stem from Perekeschkul. _Zygosporites_ sp. The object represented in fig. 41 F consists of a stalked spherical sac bearing a number of radiating arms which are divided distally into delicate terminations. We find similar bodies figured by Williamson[435] in his IXth and Xth Memoirs on the Coal-Measure plants; he includes some of them under the generic term _Zygosporites_, and compares them with the zygospores of the freshwater algae Desmideae. Hitherto these spore-like fossils have only been recorded as isolated spheres, but in the example shown in fig. 41 F there is a distinct tubular and thin-walled stalk attached to the _Zygosporites_. The specimen was found in the partially disorganised cortical tissue of a _Lyginodendron_ stem from the English Coal-Measures. It is difficult to decide as to the precise nature of the fossil, but the presence of the hyphal stalk points to a fungus rather than an alga as the most probable type of plant with which to connect it. It may possibly be a sporangium of a fungus comparable with the common mould _Mucor_, or it may be a zygospore formed by the conjugation of two hyphae of which only one has been preserved. [Sidenote: POLYPORUS.] For an example of a fossil representative of the Basidiomycetes we may turn to the excellent monograph by Conwentz on the Baltic amber trees, and quote one of the forms which he has described. _Polyporus vaporarius_ Fr. _f. succinea_[436], fig. 43, 2. In several preparations of the wood preserved by petrifaction in amber Conwentz found distinct indications of the ravages of a fungus, which suggested the presence of the recent species _Polyporus vaporarius_ Fr. With the help of the indirect evidence afforded by the pathological effects as seen in the tissues of the host-plant, and the direct evidence of the fungal mycelium Conwentz was led to this identification. The mycelium is brown in colour, in part thick-walled, and in part with thin walls, transversely septate and not much branched. In the portion of one of Conwentz’ figures reproduced in fig. 43, 2, the rents and holes in the tracheid walls are clearly shown; they afford the indirect evidence of fungal attacks, and are of the same nature as those shown in fig. 42, B, C and E. • • • • •