PELOMYXA PALUSTRIS. 77 
the vacuoles of the endoplasm, most numerously in 
the central region ; sparingly elsewhere (Pl. VII, figs. 
1-3). In examples, say 1 mm. in diameter, there may, 
Greeff says, be some hundreds. This author describes 
them as delicately-walled bodies of globular, more 
rarely oval, figure, averaging 0°012 mm. in diameter. 
Their hyaline contents are pervaded more or less by 
dark granules; and their position, form, and appearance 
give in all respects the indubitable impression of cell- 
nuclei. 
Reproduction takes place by fission, or, as has been 
more generally observed, by the formation of amoeboid 
zoospores. The amcebule, after liberation, pass into 
a resting state, and ultimately develop a flagellum, or 
vibratile filament, passing thence into the adult phase. 
Dimensions variable, mature individuals attaining 
2 mm. diameter (Greeff) ; average diameter of a quies- 
cent individual, exclusive of the pseudopodia, about 
150 p. ; 
In the ooze of ponds and ditches, especially such as 
are partially shaded, in bogs, and amongst Sphaginwm 
in stagnant water; not very frequent. 
This organism is the largest of the amoeboid rhizo- 
pods. To the naked eye it is often visible as a speck 
of semi-opaque matter—yellowish brown by trans- 
mitted light—of which the outline undergoes constant 
change. <A pocket lens of moderate power will reveal 
it with certainty under favourable conditions. 
In her admirable paper in the Linnean Society’s 
‘Journal,’ Mrs. Veley (aée Gould) has given the results 
of some years’ careful observations on the physical 
structure of Pelomyxa palustris. In confirmation of 
suggestions previously put forward by Prof. Bourne 
and Dr. Penard, she adduces definite proof of the 
nature of the rod-like structures. That they are true 
bacteria is shown (a) by their mobility and division, 
(b) by their reactions, and (c) by successful culture. 
They are referable to the genus Cladlothrie Cohn 
