598 
J. BRONTE GATENBY. 
killed instantly. I found the oocytes stained just as shown in 
my diagrams. 
The Probable Function of the Nebenkern. 
It will be seen that for some reasons I am at present unable 
tc accept the view that the Nebenkern has anything to do 
with the formation of the astral figure. Term's important 
paper, I feel, reinforces me in this (see especially his figures 
15 to 18). 
I do not find myself in a position better than that of many 
of my predecessors in-so-far as an analysis of the function of 
the Nebenkern is concerned. But I feel sure that its real role 
has not been pointed out. It seems evident that it is, in 
molluscs, a piece of cell mechanism as definite as the mito- 
chondria. I have shown that, like the mitochondria, it is 
liable to variation in time of appearance, in size, and in its 
general behaviour. It generally stains like the mitochondria, 
it is destroyed by the fixatives which also destroy mito- 
chondria, and it is seen best in preparations which show the 
latter best. I therefore think that the Nebenkern rods in 
Helix are to be classed with the two sorts of mitochondria 
described by me as 'definite plasmatic elements whose exact 
function is still unknown, but which have nothing to do with 
the amphiaster. The aster and centrosomes can be followed 
out best in material unfavourable for a study of the mito- 
chondria or Nebenkern. 
With regard to staining reactions, Faure-Fremiet says : 
“ Si Foil isole des spermatocytes dans le serum au chlorure 
de manganese additionne de violet dahlia ou de violet de 
gentiane, les mitochondries se colorent assez rapidement en 
lilias, tandis que le Nebenkern reste quelquefois plus long- 
temps avant de se colorer." 
b. Mitochondria. 
It is not intended to discuss these bodies at length, but it 
may be pointed out that in the snail one finds a remarkable 
