32 MOVEMENTS OF PROTOPLASM IN CELL-CAVITIES. 
in one direction, others on the opposite side are retracted, and the protoplast as 
a whole glides over the intervening space like a snail without its shell. The 
analogy is all the more exact since the protoplast, as it glides onward, leaves a 
slimy trail in its wake, so that the latter is marked by a streak resembling the 
track of a snail. When two or more of these creeping protoplasts, or plasmodia, 
meet, they merge into one another, flowing together somewhat in the same way 
as two oil-drops on water coalesce into one—leaving no distinguishable boundaries 
between the united bodies. Thus, slimy lumps of protoplasm, which may attain 
to the dimensions of a closed or open hand, result from the coalescence of great 
numbers of minute protoplasts. And it is a very remarkable fact that these 
plasmodia can themselves change their form, putting out lobes and threads, and 
é cae 
Fig. 9.—Creeping Protoplasm. 
creeping about in the same way as the single protoplasts from whose fusion 
they have arisen. 
Creeping masses of jelly sometimes move in the direction of incident light; at 
other times they avoid light and hide in obscure places, wriggling through the 
interstices of heaps of bark or into the hollows of rotten trunks; or they may 
creep up the stems of plants, or glide over the brown earth in a viscous condition. 
On these occasions they resolve themselves not infrequently into bands, cords, and 
threads, which surround fixed objects, divide, and combine again, forming a net-work 
of meshes, or else perhaps frothy lumps like euckoo-spit. If foreign bodies of small 
size are enmeshed by the viscous threads of the reticulum, they may be drawn 
along by the protoplasm as it creeps; and if they contain nutritive material, they 
may be eaten up and absorbed. Plasmodia are, for the most part, colourless, but 
some are brightly tinted; in particular may be mentioned the best-known of all 
plasmoid fungi, the so-called “Flowers of Tan” (Fuligo varians), which are yellow, 
and Lycogala Epidendron, which comes out on old stumps of pines, and is vermilion 
in colour. 
MOVEMENTS OF PROTOPLASM IN CELL-CAVITIES. 
In the case of a protoplast which is not naked, but clothed with an attached 
cell-membrane, the movements are limited to the space included by the membrane, 
that is to say to the cell-cavity. Until the protoplasmic cell-body is differentiated 
into distinct individual portions no very lively motion can in general take place 
in the coated protoplast; though it is not to be assumed that it abides completely 
