_a_. A bit of the plasmodiocarp, showing structure, x 6.

Fig. 6 _b_. A spore of the same species, x 1400.

_Physarum leucopus_ Link., p. 79.

Fig. 7. A single sporangium, x 15.

Fig. 7 _a_. A spore of the same species, x 900.

Fig. 7 _b_. A fragment of the capillitium.

[Illustration: PLATE IX]

EXPLANATION OF PLATE X

_Badhamia rubiginosa_ (Chev.) Rost., p. 43.

Fig. 1. A group of sporangia, x 5.

Fig. 1 _a_. Two sporangia, same species, x 18, to show persisting
capillitium.

Fig. 1 _b_. Capillitium fragment, x 240.

Fig. 1 _c_. Spore of the same species, x 750.

_Fuligo septica_ (L.) Gmel.; form _laevis_, p. 29.

Fig. 2. An aethalium, natural size.

Fig. 2 _a_. A section of the same, x 10.

Fig. 2 _b_. A spore of the same, x 750.

_Fuligo cinerea_ Pers., p. 26.

Fig. 3. A small aethalium borne upon a blade of grass, natural size.

See also Plate XXIII.

Fig. 3 _a_. Capillitial fragment from the same specimen, x 450.

Fig. 3 _b_. Spores of the same, x about 750.

_Didymium minus_ List., p. 121.

Fig. 4. A single sporangium, x 25.

Fig. 4 _a_. The capillitium and fragment of the peridium of the same
species, x 380.

Fig. 4 _b_. A spore of the same species, x 1000.

_Trichia iowensis_ Macbr., p. 269.

Fig. 5. Tip of an elater, x 1400.

See also Plate III, 3, 3 _a_, 3 _b_.

_Badhamia papaveracea_ Berk. & Rav., p. 42.

Fig. 6. Sporangia, a cluster, x 8.

Fig. 6 _a_. A cluster of spores, x 400.

Fig. 6 _b_. A single spore of the same, x 1400.

_Reticularia lycoperdon_ Bull., p. 210.

Fig. 7. A fragment of the capillitium, x 240.

Fig. 7 _a_. A single spore of the same species, x 1400.

See also Plate XII., Fig. 3.

[Illustration: PLATE X]

EXPLANATION OF PLATE XI

_Comatricha nigra_ Pers., p. 178.

Fig. 1. A group of sporangia, x 10.

Fig. 2. A single sporangium as in section, x 60.

Fig. 3. A single spore, x 1600.

_Stemonitis confluens_ Ell. & Cke., p. 158.

Fig. 4. A group of sporangia, x 10.

Fig. 4 _a_. A thread of capillitium with adhering disk, x 30.

Fig. 5. A spore of the same, x 2000.

_Stemonitis webberi_ Rex, p. 163.

Fig. 6. A group of sporangia, x 4.

Fig. 7. A single sporangium as in section, x 40.

Fig. 8. A single spore, same species, x 1250.

_Comatricha suksdorfii_ Ell. & Ev., p. 178.

Fig. 9. A group of sporangia, x 4.

Fig. 10. A bit of the capillitium, x 60.

Fig. 11. A single spore, x 1600.

_Coma