208 
ENDOSPORE>E. 
[lycogala. 
more or less separated from each other by narrow tubular air-passages. 
Sections of such an a3thalium, when hardened and stained, show the 
inner veins to measure fi-om 40 to 50 /x diam., while the more super- 
ficial veins are about 100 /x diam. At a later stage the outer convolu- 
tions become deeply lobed, flattened and folded on themselves ; tubular 
air-passages are enclosed between the folds, which, together with the 
deeper air-passages and the surface of the sethalium, are bounded by 
a delicate membrane. At a still later stage, when the cortex is form- 
ing, the periphery is differentiated into two layers, an outer and an 
inner. The former bears on its surface isolated thick-walled lobes 
or vesicles, 20 to 200 ^ diam., containing nucleated, deeply-staining 
protoplasm ; the nuclei remain sharply defined till after the spores 
are formed in the aethalium, when they degenerate and disappear. 
This outer layer consists of unstaining, hyaline substance, destitute 
of nuclei, and traversed by thick-walled interlacing air-passages. The 
inner layer is finely granular, faintly staining, homogeneous, and 
devoid of nuclei ; through it the air- passages of the cortex communi- 
cate with those of the interior ; the latter remain thin-walled, and 
form the so-called capillitium. In examining a young aethalium after 
the cortex has formed, but some hours before the karyokinetic division 
of nuclei, preparatory to the formation of spores, takes place, the 
capillitium tubes are found to be completely formed, and are filled 
with air, though lying in the fluid sporeplasm. This appearance shows 
that they are the air-spaces which existed among the convoluted 
sporangia when producing the aethalium, bounded by a membrane 
corresponding to sporangium-walls. In L. flavo-fuscum this membrane 
is more delicate than in L. miniatum, and is in some parts perforated 
with irregular lattice-work openings. The presence of spores in the 
tubes, which is occasionally found in L. flavo-fuscum, may be explained 
by the penetration of sporeplasm through such openings. 
KEY TO THE SPECIES OF LYCOGALA. 
Cortex of sethalia smooth or areolated. 1. L. Jlavo-fuscum 
Cortex of sethalia warted — 
^thalia subglobose. 2. L. miniatum 
^thalia conical. 3. L. conimm 
1. L. flavo-fuscum Host., Versuch., p. 3 (1873). Plasmodium? 
^thalia rounded, sessile, or subpyriform, and shortly stalked, 
2 to 5 cm. diam., ochraceous-brown or purplish -brown, smooth, 
minutely areolated; cortex thick, of three layers, the outer 
membranous, the middle consisting of a dense aggregation 
of yellow vesicles, 50 to 80 /x diam., intermixed with the peri- 
pheral ends of the capillitium, the inner layer homogeneous, 
pierced by the capillitium threads ; mass of capillitium and spores 
pale bufe. Capillitium of irregularly branching, nearly colourless, 
wrinkled tubes, 6 to 20 diam., or more, with numerous blunt- 
ended free branches. Spores almost colourless, minutely reticu- 
lated over the greater part of the surface, 5 to 6 ^ diam.— Mon., 
p. 288 ; Cooke, Myx. Brit., p. 76 ; Macbride, in Bull. Nat. Hist. 
Iowa, ii., p. 127 ; Mass. Mon., p. 124; Zopf, in Schenk, Haudb. 
der Bot., ui., 2, p. 167. Diphtherium flavo-fuscum Ehrenberg, 
Sylv. Myc. Berol., pp. 14, 27 (1818). 
