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tractile vesicle, and never retracts its processes, which, again, 
are always less numerous. Any confusion, however, will 
always be prevented hv observance of the rapid movements 
in one direction which these Radiolaria present. 
By far the greater part of the marine Radiolaria bears a 
hard trellised shell and firm spines, spiculae, hooks, &c. The 
fresh-water Radiolaria being shell-less and unprotected, their 
structure is consequently more simple, and they will therefore 
fall into a place in systematic arrangements before the more 
protected marine Radiolaria — according to HackeFs system, 
before Tlialassicola — and thus extend the ranks of the 
Radiolaria. 
Dr. Focke gives full details concerning these species of 
shell-less fresh-water Radiolaria, and refers the reader to 
appended illustrative plates. 
No. 1. — The first species presented at first sight four green 
globules, surrounded by a border of sarcode and needle-shaped 
and tongue-like processes. Division processes were indicated 
by the fact that these globules were found in other specimens 
in groups of two, eight, and sixteen. The granules within the 
enveloping membrane, particularly those near the periphery 
of the body, were subjected to rapid movements. In these 
forms the sarcode layer and processes can scarcely be di 
