XXV. _CHRYSOTHRICACEAE._ Thallus felted, loose in texture. Algal cells _Palmella_, Protococcaceae or _Trentepohlia_. Apothecia with or without a thalline margin. The affinity of the “Family” seems to be with Pilocarpaceae. XXVI. _THELOTREMACEAE._ } Thallus crustaceous. Algal cells in the XXVII. _DIPLOSCHISTACEAE._ } first _Trentepohlia_; in the second } Protococcaceae. In both there are } prominent double margins round the } apothecium. XXVIII. _ECTOLECHIACEAE._ Thallus very primitive in type. Algal cells Protococcaceae. Apothecia with or without a thalline margin. Nearly related to Chrysothricaceae. XXIX. _GYALECTACEAE._ Thallus crustaceous. Algal cells _Trentepohlia_, _Phyllactidium_ or rarely _Scytonema_. Apothecia biatorine, _i.e._ of soft consistency and without gonidia. XXX. _COENOGONIACEAE._ Thallus confusedly filamentous (byssoid). Algal cells _Trentepohlia_ or _Cladophora_. Apothecia biatorine. XXXI. _LECIDEACEAE._ Thallus crustaceous or squamulose. Algal cells Protococcaceae. Apothecia biatorine (soft), or lecideine (carbonaceous). XXXII. _PHYLLOPSORACEAE._ Thallus squamulose or foliose. Algal cells Protococcaceae. Apothecia biatorine or lecideine. XXXIII. _CLADONIACEAE._ Thallus twofold. Algal cells Protococcaceae. Apothecia biatorine or lecideine. XXXIV. _GYROPHORACEAE._ Thallus foliose. Algal cells Protococcaceae. Apothecia lecideine. XXXV. _ACAROSPORACEAE._ Thallus primitive crustaceous, squamulose or foliose. Algal cells Protococcaceae. Apothecia with or without a thalline margin; very various, but always with many-spored asci. 2. _Cyanophili group._ In this group the classification depends almost entirely on the nature of the algal constituents. The apothecia are in most genera provided with a thalline margin. _a. More or less gelatinous when moist._ XXXVI. _EPHEBACEAE._ Algal cells _Scytonema_ or _Stigonema_. Thallus minutely fruticose or filamentous. XXXVII. _PYRENOPSIDACEAE._ Algal cells _Gloeocapsa_ (_Gloeocapsa_, _Xanthocapsa_ or _Chroococcus_). Thallus crustaceous, minutely foliose or fruticose.