65 
takes part in it. He does not determine how their connection 
came about, whether when very minute or after growth, or 
whether they were ever separate at all. The coccospheres 
Haeckel found to be excessively rare. He, however, found 
the granular zone present in their component coccoliths, which 
Huxley did not. He found them made up either of oval or 
round discoliths, or of cyatholiths, the coccoliths in one cocco- 
sphere being nearly always of the same kind. He agrees 
with Huxley that it is improbable that the coccoliths result 
from the breaking up of the coccospheres. At the same time 
his detection of the granular zone proves the absolute identity 
of the two in structure. 
The most important part of Haeckel’s researches in this 
matter is now to be mentioned ; we have briefly called atten- 
tion to it in our last volume. In February, 1867, Haeckel 
found floating on the surface of the sea numbers of a new 
Radiolarian—allied to the Thalassicolle—which he proposes 
to call Myzxobrachia, and which contains concretions em- 
bedded in its extra-capsular sarcode, which are identical with 
the coccoliths and coccospheres. 
Myxobrachia is very large, seeing that it is one of those 
Radiolarians having but one central capsule, namely, about 
half an inch long. ‘Two species are distinguished, one J. 
rhopalum (Pl. V, fig. 1), pear-shaped, floating with the 
larger part just on the surface of the sea, and the stalk-end 
hanging down; the upper part contains the central capsule: 
the depending process has an axis of the yellow cells charac- 
teristic of Radiolaria, and a mass of calcareous concretions at 
the end. The second species, JM. pluteus, looks like an 
Echinoderm larva; it has exactly the same structure as WM, 
rhopalum, but in place of one process depending there are 
sixteen arranged in three rows (PI. V, fig. 2). The calcareous 
concretions in this present the closest resemblance to the 
coccoliths and coccospheres, but Haeckel will not assert ab- 
solutely their identity. Both species are capable of elongating 
and contracting themselves, and are beset with short pseudo- 
podia. The central capsule (figs. 1, 2cc) is about one millimetre 
in diameter, perforated by fine pore-canals. It contains a vesi- 
cula intima (fig. 3), which is constricted into a number of 
oblong bladders radially,as in Thalassicolla pelagica. Between 
it and the wall of the central capsule are numerous small 
cells (the truly cellular nature of these probably reproductive 
bodies, as seen in their nuclei, is important), and protoplasmic 
fluid. There are also floating in this space numerous blood- 
red oil-globules. The mass of the body is composed in both 
Myxobrachiee of sarcode jelly, which is relatively more abund- 
