In _Graphis scripta_ (fig. 26) the thallus is thin, somewhat membranous, smoothish, shining, greyish white, and faintly bordered with black. The lirellæ (fig. 27) are partly sunk in the bark, winding and narrow, some being simple, others branched; and they are surrounded by a raised border, formed by the thallus. The lirellæ are lined at the sides with a black (carbonaceous) layer or _excip´ulum_, within which are situated the asci and paraphyses. The spores (Pl. II. fig. 29) are 8-cleft, the segments being again divided longitudinally into little spores or sporidia. In _Opegrapha betulina_ (Pl. II. fig. 30), which is found on the bark of the birch-tree, the thallus is thin, dirty yellowish white, bordered with black. The lirellæ (figs. 31, 32) are mostly simple, without a raised border of the thallus, and the excipulum forms a complete lining to them. The spores (fig. 33 _a_) are 3-cleft, and taper at the ends. CALICI´EÆ.--_Calic´ium clavel´lum_ (Pl. II. fig. 6) is a pretty little Lichen, growing upon old boards and farm-buildings. The thallus is granular and greyish white. The apothecia (fig. 7) are stalked and black, but of a lighter colour than the mass of spores forming the nucleus. The spores are very minute, black, oblong, and divided by a transverse septum. The Lichens are divided into two Orders, according to whether the apothecia are open before the spores are ripe, as in the species noticed above, or whether the apothecia only open to discharge the ripe spores. The first Order forms the _Gymnocar´pi_ (γυμνὀς, naked, καρπὀς, fruit); the second forms the _Angiocar´pi_ (ἁγγεῖον, vessel, capsule). _Preservation._--The Lichens are readily preserved, on account of their dry nature; they need simply be kept in a dry place, and glued to pieces of card. If room is an object, they may be dried under pressure, as in the case of the flowering plants. When re-moistened, the minute structures may be easily made out by sections. The smaller ones may be mounted dry, in cells made of the wax cement (p. 16). The minute structures keep well in chloride of calcium or glycerine. CHAPTER IX. FUNGI. The Fungi form the lowest class of plants: as examples of them, may be mentioned mushrooms, toadstools, puff-balls, the mould of paste, the blue mould of cheese, &c. The more minute Fungi are very common, forming beautiful microscopic objects, although they are rarely studied by the microscopic observer. Fungi live usually upon rotting or decaying vegetable substances, as rotten wood, the dead leaves and stems of plants, &c.; but sometimes they are found upon living plants, and some of them exist upon decaying animal matters, and even in living animals.