Enrlij Protozoa. — Mattheir. 151 
than all the others united, as from it are drawn all the data 
for the plate published with his article. 
The care he took to eliminate the "personal equation'' may 
be inferred from his statement that he had a special artist 
emploj^ed, who had never drawn radiolarians, to draw the fig- 
ures for the plate, and who figured ''/*/.v^ u-h«f he sair''^ on the 
slide. 
Mr. Caj^eux remarks that there is an advantage in studying 
these radiolarians first with a low power, as therebj'^ one can 
see their irregular distribution; they multiply in some places 
so as to touch each other, and in others they are represented 
by but few individuals. It was after using objectives of high 
power that Mr. Cayeux was able to resolve the apparently 
small spheres into a greater variet}^ of shapes; he describes 
them under the following hea>.ls : 
1. Radiolarians idknticai, avitii known genera. 
Legion SpinaeU(tri((, Ehr. 
Cenosphivnt several species, Carpospharit^ Xiphospha ra^ 
iSfauffi'spha'ra, .1 canthospha ra. Cencllipsis. Spoin/iinis, 
Legion Xds.selaria, Haeck. 
Tripoc(i//)i.s, Tr/j)0(l/sciiiiii. Archicorys, (.' iirfocalpls^ Diftyo- 
ceph((h/.s, Sfefhocajtsa, JJicolocapsa, 'J'heocauipc. 
2. Radiolarians whose reference to knoavn (jenera is uncer- 
tain. . 
Some of the above genera nnd Tridcfoum. Lit Inijiiinu . ^\ii- 
t/ioci/rfis. 
3. Forms undetermined, iu t wnrc h are certaini.v Radiola- 
rians. 
All these are referable to the above legions, and to families 
of the genera above named. 
After describing the forms, Mr. Cayeux mentions and re- 
futes the various objections made to his reference of these 
fossils to the radiolarians. Among these objections is the 
claim that these spherules are too small to be referred to radi- 
olarians, and that there is no visible reticulation of the test. 
It seems to the present writer that the small size of these ob- 
jects is no bar to their being radiolarians, for such a relation 
of tlie primitive types to the fully developed forms is (piite in 
keeping with the history of other organisms. 'J'akc. for ex- 
ample, some of the earlier Paheozoic trilobitcs: the initial 
