Perithecia with simple ostioles. Paraphyses disappearing early, or wanting. Spores simple, ellipsoid 1. Verrucaria Web. Spores simple, elongate vermiform 2. Sarcopyrenia Nyl. Spores simple, numerous in the ascus 3. *Trimmatothele Norm. Spores 1-3-septate 4. Thelidium Massal. Spores muriform (with transverse and longitudinal divisions). Without hymenial gonidia 5. Polyblastia Massal. With hymenial gonidia 6. Staurothele Norm. Paraphyses present. Spores simple. Without hymenial gonidia 7. Thrombium Wallr. With hymenial gonidia 8. *Thelenidia Nyl. Spores 3-septate, broadly ellipsoid 9. *Geisleria Nitschke. Spores acicular, many-septate 10. Gongylia Koerb. Spores muriform 11. Microglaena Lönnr. Perithecia with a wide ring round the ostiole. Spores muriform; paraphyses unbranched 12. *Aspidothelium Wain. Spores elongate, many-septate; paraphyses branched 13. *Aspidopyrenium Wain. IV. _DERMATOCARPACEAE_ In this family there is a much more advanced thalline development—generally squamulose or with some degree of foliose structure, though in the genus _Endocarpon_, some of the species are little more than crustaceous. The gonidia are bright-green Protococcaceae (according to Chodat, _Coccobotrys_ in _Dermatocarpon_). In _Endocarpon_ they appear in the hymenium. The least developed in structure is _Normandina_: the thallus of the single species consists of delicate shell-like squamules which are non-corticate above and below. In the other genera there is a cortex of plectenchyma. The perithecia are almost wholly immersed, and open above by a straight ostiole. The fructification of _Dacampia_ is considered by some lichenologists to be only a parasite on the white thickish squamulose thallus with which it is associated. Hymenial gonidia present. Spores muriform 1. Endocarpon Hedw. Hymenial gonidia absent. Thallus non-corticate 2. Normandina Wain. Thallus corticate. Spores simple, colourless 3. Dermatocarpon Eschw. Spores simple, brown 4. *Anapyrenium Müll.-Arg. Spores elongate-septate, colourless 5. *Placidiopsis Beltr. Spores elongate-septate, brown 6. *Heterocarpon Müll.-Arg. Spores muriform, colourless 7. *Psoroglaena Müll.-Arg. Spores muriform, brown 8. Dacampia Massal. V. _PYRENOTHAMNIACEAE_ Thallus more or less fruticose and corticate on both surfaces. Algal cells Protococcaceae.