_Physarella oblonga_ (Berk. & C.) Morgan, p. 109. Fig. 1. Fully opened sporangium, x 10. Fig. 1 _a_. Tubular sporangia closed, x 5. Fig. 1 _b_. Transverse section of sporangium; shows trabecular calcareous nodules of the capillitium, x 15. _Craterium cylindricum_ Mass., p. 106. Fig. 2. Group of sporangia, x 10. _Physarum wingatense_ Macbr., p. 72. Fig. 3. Group of sporangia, x 10. _Physarum albescens_ Ellis, p. 86. Fig. 4. Group of sporangia, x 10. Fig. 4 _a_. Capillitium of the same species, x 200. _Dianema harveyi_ Rex, p. 238. Fig. 5. Group of sporangia, x 10. Fig. 5 _a_. Clustered spores, D. corticatum, x 500. Fig. 5 _b_. Capillitial threads and spores, D. harveyi, x 200. Fig. 5 _c_. Twisted, spirally striate single threads, x 500; _D. corticatum_, List. _Physarella oblonga_ Berk. & C., p. 109. Fig. 6. Terrestial, plasmodiocarpous phase, x 10. _Physarum megalosporum_ Sturg., p. 63. Fig. 7. Group of sporangia, x 8. Fig. 7 _a_. Capillitium and spores, x 150. _Didymium complanatum_ (Batsch) Rost., p. 116. Fig. 8. Capillitial structure, x 200. _Physarum wingatense_, p. 72. Fig. 9. Sporangium, x 20, enlarged to show dehiscence. _Didymium xanthopus_ (Ditm.) Fr., p. 123. Fig. 10. Sporangium--diagram to show columella, x 20. _Didymium eximium_ Pk., p. 124. Fig. 11. Group of sporangia, x 10. Fig. 11 _a_. Section of sporangium, x 30; diagram. Fig. 11 _b_. Spore, x 750. Comatricha elegans (Racib.) List., p. 182. Fig. 12. A single sporangium, x 20. Clastoderma debaryanum, p. 191. Fig. 13. Sporangium, seen in section, x 20. Stemonitis herbatica Pk., p. 171. Fig. 14. Group of sporangia, x 2. Fig. 14 a. The same enlarged to show general outline. Fig. 14 b. The same; capillitial section, x 20. Fig. 14 c. A single spore, x 1000. [Illustration: PLATE XVI] EXPLANATION OF PLATE XVII _Cribraria argillacea_ (Pers.) Schrad., p. 218. Fig. 1. Sporangium, highly magnified. _Cribraria macrocarpa_ Schrad., p. 219. Fig. 2. Sporangium, highly magnified. _Cribraria aurantiaca_ Schrad., p. 221. Fig. 3. Sporangium containing spores, x 30. _Cribraria microcarpa_ Schrad., p. 226. Fig. 4. Sporangium containing spores, x 30. _Cribraria tenella_ Schrad., p. 225. Fig. 5. Sporangium containing spores, x 40. _Cribraria minutissima_ Schw., p. 220. Fig. 6. A single sporangium calyculate, x 50. Fig. 6 _a_. A smaller sporangium without calyx, with spore-mass. _Cribraria cuprea_ Morg., p. 229. Fig. 7. A single sporangium, x 50. _Cribraria violacea_ Rex, p. 227. Fig. 8. A single sporangium, x 40. _Cribraria piriformis_ Schrad., p. 224. Fig. 9. A single sporangium, x 30. _Perichaena depressa_ (Libert) Rost., p. 242. Fig. 10. A cluster of sporangia, one open, x 8. _Physarum nicaraguense_ Macbr., p. 83. Fig. 11. Single sporangium, x 10. Fig. 11 _a_. A cluster of sporangia and hypothallus, x 5. [Illustration: PLATE XVII] EXPLANATION OF PLATE XVIII _Margarita metallica_ (Berk. & Br.) List., p. 237.