CHAPTER VIII-—MORPHOLOGYF AND COURSE OF DEVELOPMENT. 447 
pear-shaped, conical at the smaller end and running out into a very strong flagellum ; 
movement that of the swarm-cells of the Myxomycetes. The spores when they come 
to rest creep about in the manner of the Amoebae.’ Such is Haeckel’s diagnosis. 
This organism differs from the Myxomycetes chiefly in the absence of firm spore- 
membrane, and in the circumstance that neither cell-nucleus nor division of the swarm- 
cells has been observed. Myxastrum radians, Haeckel, also a marine form and dis- 
tinguished by the presence of silica in the spore-membranes, appears to be nearly 
allied to Protomyxa. 
Cienkowski’s Vampyrellae are organisms with amoeboid movement which live 
on Algae and Diatoms. Some like Vampyrella Spirogyrae and V. pendula suck the pro- 
toplasm and chylorophyll-corpuscles from out of the living cells of species of Spirogyra 
or Oedogonium, when they have pierced their walls, while V. vorax embraces the entire 
cells of Diatoms, Desmids and similar forms with their pseudopodia, and absorbs them 
into its own substance. In both cases the reception of a certain quantity of food is 
followed by a period of rest, a smoothing of the surface of the body and the excretion 
of a delicate firm membrane. In this state of rest the bodies which have been 
absorbed are digested, that is are dissolved till there remain only comparatively minute 
portions of the protoplasm which have assumed a brown colour, and in the case of 
Vampyrella vorax of the membranes. Next follows the excretion of the undigested 
substance from the living protoplasm, the division of the latter into usually 2-4 swarm- 
cells and their escape from the membrane; the two processes go on simultaneously, 
the division being effected while the spores are escaping at 2-4 separate points. Then 
according to J. Klein from 2-4 swarm-cells, seldom more, at once coalesce again 
and form a plasmodium, which repeats the process just described of absorption of 
food and subsequent formation of swarm-cells. In addition to this course of develop- 
ment resting cysts may also be formed, in which case the body which has come to 
rest inside the membrane excretes undigested remains of the food, and then without 
forming 8warm-cells excretes a new membrane. The subsequent fate of these cysts 
is still unknown. Other transitory states of rest, as in the small cysts of the 
Myxomycetes, may occur within the periodic course of development described above, 
and no coalescence may take place, the cells passing singly through the swarming 
state as above but not forming plasmodia. 
Cienkowski’s Nucleariae appear to be just like the Vampyrellae in the 
course of their development and in their manner of life. They are distinguished 
from them by the presence of nuclei, which are said to be wanting in the Vampy- 
rellae. Coalescence into plasmodia has not been observed in them, but it is not 
excluded by the ascertained facts. 
Cienkowskis Monas Amyli has motile swarm-cells provided with two cilia, 
and a number of these cells surrounding a starch-grain may coalesce into small 
plasmodia. The plasmodium forms a membrane, and after its substance has increased 
in size at the expense of the starch-grain it produces a large number of new swarm- 
cells by simultaneous division. It is said also that a single swarm-cell may spread 
itself round a grain of starch without uniting with others to form a plasmodium, 
and thus become the starting-point of the development which was described above. 
An exactly similar course of development has been observed in Klein’s 
Monadopsis and Cienkowski’s Pseudospora and Colpodella, except that the latter 
