istory of the subject. Some of these forms we
here venture to describe, with such annotation as may show something of
present knowledge.

=Key to the Species of Fuligo=

_A._ Aethalium 1 cm. or less; spores spherical 1. _F. muscorum_

_B._ Aethalium larger, or plasmodiocarpous, even
sporangi-form, crust white, smooth, even,
spores elliptical 2. _F. cinerea_

_C._ Aethalia larger, 2 cm. or more.

1. Cortex yellow, etc., not white; spores 6-8 mu 3. _F. septica_

2. Cortex nearly or quite wanting; spores
10-12 4. _F. intermedia_

3. Cortex white, a foamy crust; spores 15-25 5. _F. megaspora_

1. FULIGO MUSCORUM _Alb. & Schw._

1894. _Fuligo muscorum_, Alb. & Schw. Lister, _Mycetozoa_, p. 67.
1875. _Licea ochracea_ Peck, N. Y. _Rep._, XVIII., p. 55.
1879. _Fuligo ochracea_ Peck, N. Y. _Rep._, XXXI., p. 56.
1894. _Fuligo muscorum_, Alb. & Schw., Lister, _Mycetozoa_, p. 67.
1911. _Fuligo muscorum_ Alb. & Schw., Lister, _Mycetozoa, 2nd ed._,
p. 87.

Plasmodium orange-yellow. Aethalium globoid, very small, 1 cm. or less,
the cortex very thin, greenish yellow; sporangial walls not evident;
capillitium well-developed, the numerous calcareous nodes fusiform or
often branching, and connected by rather short, transparent internodes;
spores coarsely warted, 10-11 mu.

This form seems to differ from _F. septica_ chiefly in its constant
diminutive habit of fruiting, in its delicate cortex, and in its spores,
brighter, larger, and more coarsely warted. The descriptions and figure
by Schweinitz seem referable to nothing else. First reported by
Albertini and Schweinitz from Germany; by Schweinitz from the Carolinas;
then by Dr. Peck described as a _Licea_ from New York. It seems less
commonly collected in the United States.

2. FULIGO CINEREA (_Schw._) _Morg._

PLATE X., Figs. 3, 3 _a_, and 3 _b_, and Plate XXIII.

1831. _Enteridium cinereum_ Schw., _N. A. F._, No. 2365.
1875. _Physarum ellipsosporum_ Rost., _Mon. App._, p. 10.
1884. _Aethaliopsis stercoriformis_ Zopf., _Pilzthiere_, p. 150.
1894. _Fuligo ellipsospora_ Lister, _Mycetozoa_, p. 67.
1896. _Fuligo cinerea_ (Schw.) Morg., _Cin. Soc. Nat. Hist._, p. 105.
1899. _Physarum ellipsosporum_ Rost., Macbr. _N. A. S._, p. 27.
1911. _Fuligo cinerea_ Morg., List., _Mycetozoa_, 2nd ed., p. 88.