The vacuolated cell-contents partially filling the cells in fig. 41, D, present a striking resemblance to the contents of the cells 2–5 in fig. 41, A. In fig. D the frothy and contracted substance might be easily mistaken for a parasitic or saprophytic fungus, but this resemblance is entirely misleading. It is by no means uncommon to find the cells of recent plants occupied by such vacuolated contents, especially in diseased tissues in which a pathological effect produces an appearance which has more than once misled the most practised observers. In the important work recently published by Renault on the Permo-Carboniferous flora of Autun, there is a small spore-like body described as a teleutospore, and classed with the Puccineae[420]. We have as yet no satisfactory evidence of the existence of this section of Fungi in Palaeozoic times, and Renault’s description of _Teleutospora Milloti_ from Autun might be seriously misleading if accepted without reference to his figure. The fragment he describes cannot be accepted as sufficient evidence for the existence of a Palaeozoic _Puccinia_. The same author refers another Palaeozoic fungus to the Mucorineae under the name of _Mucor Combrensis_[421]; this identification is based on a mycelium having a resemblance to the branched thallus of _Mucor_, but in the absence of reproductive organs such resemblance is hardly adequate as a means of recognition. The occurrence of hyphal cells in calcareous shells and corals has already been alluded to.[422] In addition to the examples referred to above, there is one which has been described by Etheridge[423] from a Permo-Carboniferous coral. This observer records the occurrence of tubular cavities in the calices of _Stenopora crinita_ Lonsd., and attributes their origin to a fungus which he names _Palaeoperone endophytica_; he mentions one case in which a tube contains fine spherical spore-like bodies which he compares with the spores of a _Saprolegnia_. As pointed out above (p. 128), it is almost impossible to decide how far these tubes in shells and corals should be attributed to fungi, and how far to algae. [Illustration: FIG. 41. A. Cells of _Cycadeoidea gigantea_ Sew. × 355. B and C. Parenchymatous cells and scalariform tracheids of _Osmundites Dowkeri_ Carr. × 230. D. Epidermal cells of _Memecylon_ (_Melastomaceae_) with vacuolated contents. E. _Peronosporites antiquarius_ Smith, (No. 1923 in the Williamson collection). × 230. F. _Zygosporites_. × 230. (A, B, C and E drawn from specimens in the British Museum; D from a drawing by Prof. Marshall Ward; F from a specimen in the Botanical Laboratory Collection, Cambridge.)] [Illustration: FIG. 42. A, B, C. Tracheids of coniferous wood attacked by _Trametes radiciperda_ Hart. (_Polyporus annosus_ Fr.) D and E. Tracheids attacked by _Agaricus melleus_ Vahl. A, × 650, B–E, × 360. (After Hartig.)]