10 
INTRODUCTION. 
In a few instances a large nucleus encloses two nucleoli, and 
occasionally there are appearances which strongly suggest that 
simple division of a nucleus is taking place. Some days later, 
Avhen the plasmodiiim had ceased to feed, and was collecting 
together to form into sporangia, stainings showed the nuclei more 
equal in size, measuring 4 to 5 /a in diameter. This experiment 
may be taken to add matei'ially to the negative evidence, to say 
no more, that under some conditions the increase in the number 
of the nuclei is produced by simple division. 
The Plasmodium of the exosporous Ceratiomyxa issues from the 
interior of rotten wood to form cushion-like heaps which rapidly 
extend into columnar or branching sporophores. ' As the stream- 
ing movement common to both divisions of the Mycetozoa is not 
described by Famintzin and Woronin in their valuable paper on 
Ceratiomyxa before alluded to, the following observations may be 
given. Rounded cushions of plasmodium were placed on a cover- 
slip, supported at the margins by wet blotting-paper, and were , 
thus enclosed in a moist chamber. The plasmodium spread in a 
film over the glass, and here eventually an abundant growth of 
spores was produced. At the earliest stage that could be ob- 
served under the microscope the plasmodium was seen to be 
sharply differentiated into two elements — a hyaline part which 
ultimately forms the principal constituent of the gelatinous 
cokimn, and the granular protoplasm containing numei^ous small 
nuclei. In the film on the cover-glass the granular substance 
spread in a network of veins through the hyaline portion. Through 
these veins the protoplasm streamed in rhythmic flow, first in one 
direction and then in the other, at the same intervals of time as 
in the Endosporece. 
The Sclerotium. — Superficial plasmodia may pass into the resting 
stage or sclerotium, and this change may be induced by exposvire 
to dry air. In some cases, however, it occurs when water and 
apparently food material are present, and the cause for the change 
is then difiicult to discover. When the plasmodium of Baclhamia 
utricidaris is dried, the streaming movement gradually ceases, 
and the granular particles collect in clusters, surrounded by a 
border of hyaloplasm ; the refuse matter is thrown out, and a 
membranous cyst-wall forms round each cluster of granules, 
which also includes 10 to 20 nuclei; the cysts become agglomer- 
ated into thick masses of irregular shape, drying to a horny 
consistence.* The changes of outline seen in the maturing 
sclerotia cannot be merely the eflect of shrinking from di-ying, 
and as under the microscope we frequently observe the cj'sts 
along the margin of a forming sclerotium creep among each other 
with amoeboid movement, it is probable that this movement takes 
place throughout the mass. The sclerotium of this species can 
be revived after preservation in a dry state for three years, by 
* Lister, " On riasmodium of Baclhamia and Bi'cfeklia," Ann. Bot., vol, ii., 
1888, p. 13. 
