72 
in the field of the microscope, to state precisely whether this 
or that process stands in the same row, or is placed above or 
below the other. 
The fundamental form of the fresh-water Radiolaria seems 
to be the sphere, but this does not, however, preserve the 
stability which, in the majority of Rhizopods, is dependent 
upon the shell, nor does it present that rapid, proteus-like 
change of form shown by the Amoebae, &c. The spherical 
contour may, indeed, be converted into an oval or becomes 
a triangular one, with very rounded angles, when external 
influences are not opposed. When the determined direction 
of the creature’s movements is obstructed the whole body 
flows in an irregular and elongated form about the obstruct- 
ing object, and seeks the nearest passage; next follows an 
irregular, unsym metrical distribution of the sarcode pro- 
cesses on its surface. These changes in form take place 
slowly, and the previous condition is slowly regained. 
To the clear, sharply defined, and vacuole-like spot occasion- 
ally observed within the central capsule the less importance 
is to be attached, as the specimens which presented this had 
probably ceased to live. 
Neither an accurate determination of the size of these 
creatures, nor more precise details as to colour can be given. 
The division processes appear to reduce the diameter of the 
central capsule. No measure of full-grown specimens can as 
yet be given, and the variable form of the body stands in the 
way of this. The size of the species described in this report 
fluctuates between — tV” - The colour appears only 
darker or lighter, with changes in the illumination ; the rela- 
tion, however, between the coloured and transparent granules 
in the sarcode undergoes change, and the coloration conse- 
quently acquires an altered character. The observed tints of 
green and red correspond more to the colours of the Infusoria 
than to those of chlorophyll and the red Algae. With regard 
to the sarcode no further information can as yet be given in 
addition to that already dealt with by other observers in 
good works on the Rhizopoda, &c. The hitherto obscured 
divergence of the processes in a radiating direction hardly 
permits the notion that a fusion of any of these processes 
generally takes place, and such has not yet been made out 
during processes of division. Very frequently the most 
flattened processes are filled with plasma-corpuscles. 
The fresh-water Radiolaria cannot be easily confounded 
with allied Rhizopoda, and as the first glance finds something 
so characteristic, they cannot be considered as Desmidiacese. 
Actinophrys is very similar in form, but possesses a con- 
