DEXDEOSOMA RADEANS, EHRENBERO. 
153 
lines are ill-defined and the difference between the nieo'a- 
nncleus proper and scattered chroraidia impossible to dis- 
tinguish ffigs. 12, 13, 14). 
If the form and distribution of the meganucleus of Dendro- 
soma are remarkable, still more so is its minute structure. 
The difference between the meganucleus of Den drocometes 
and that of Dendrosoma in this respect is very striking, and 
the first cause we had to doubt the current view that the so- 
called ‘‘ external buds ” (Urnula) are really produced by the 
Dendrosoma was the difference we observed in histological 
detail between the meganucleus of these bodies and the 
mesranucleus of the Dendrosoma. 
We described in a former paper (16) the meganucleus of 
Dendrocometes as consisting of a distinct meshwork of 
darkly staining lines which appears to support a series 
of minute, rounded, chromatin granules.'’^ In the meshes 
of the darkly staining chromatin there is a homogeneous sub- 
stance which stains faintly yellow with brazilin.” 
In the meganucleus of Dendrosoma we have found no trace 
of a true limiting membrane or of a meshwork. It consists 
simply of a number of chromatin granules floating indepen- 
dently in a fluid matrix (fig. 52). In this respect, therefore, 
the structure of the meganucleus appears to be very ex- 
ceptional. 
We have not arrived at these conclusions without very 
careful study and numerous experiments. We expected to 
find some kind of network, whether of plastin or of chro- 
matin, such as we found in De n d roco metes , Ur n ula, and 
some other Acinetaria, but the various methods we have em- 
ployed have given us no positive results. Staining with 
hmmatoxylin and congo-red we have obtained very shai-p 
differentiation of the histological structures, and in some 
sections we have seen a thin line bounding the meganucleus 
which might well be mistaken for a membrana limitans, but 
after prolonged research we are convinced that this line does 
not represent a continuous membrane, and that it belongs, not 
to the nucleus, but to the surrounding cytoplasm. Whether 
