_B._ Transverse section of a Lepidodendroid leaf, of which the inner tissues have been destroyed and the cavity filled with coprolites; simulating a sporangium containing spores. (A and B from specimens in the Botanical Laboratory collection, Cambridge.)] [Sidenote: TRACES OF WOOD-BORERS IN PETRIFIED TISSUE.] There is one other form of pitfall which should be briefly noticed. In sections of petrified plants one occasionally finds clean cut canals penetrating a mass of tissue, and differing in their manner of occurrence and in their somewhat larger size from ordinary secretory ducts. Such tunnels or canals are probably the work of a wood-boring animal. An example is illustrated in fig. 24 _A_. Similarly it is not unusual to meet with groups or nests of spherical or elliptical bodies lying among plant tissues, and having the appearance of spores. Such spore-like bodies appear on close examination to be made up of finely comminuted particles of tissue, and in all probability they are the coprolites of some xylophagous animal. Examples of such coprolites are shown in fig. 24 _A_[154], and in fig. 24 _B_ an interesting manner of occurrence of these misleading bodies is represented. The framework of cells enclosing the nest of coprolites in fig. 24 _B_, represents the outer tissues of a Lepidodendroid or a Sigillarian leaf; the inner tissues have been destroyed and the cavity is now occupied by what may possibly be the excreta of the wood-eating animal. Some of the oval spore-like structures met with in plant tissues may, as Renault has suggested, be the eggs of an Arthropod[155]. In a section of a calcareous Coal-Measure nodule in the Williamson collection (British Museum)[156] there occur several fungal spores or possibly oogonia lying among imperfectly preserved Stigmarian appendages. Associated with these are numerous dark coloured and larger bodies consisting of a cavity bounded by a simple membrane; the larger bodies may well be the eggs of some Arthropod or other animal. [Sidenote: PHOTOGRAPHY AND ILLUSTRATION.]