lvi 
then separates into two secondary vesicles. These two vesicles or 
cells are the rudiments of the future male and female generative 
organs. Each of them becomes gradually covered by a generation 
of small cells, which, when once produced, continue to increase in 
size, and multiply on their own account. The group produced by 
the herniated vesicle engrafted on the epithelium represents the 
male element, and gives origin to the fecundating corpuscles ; that 
which originates from the free vesicle remaining within the blasto- 
derm produces the future female generative organs. The generative 
vesicle of the male mass increases its size, attaches itself to the 
female generative apparatus, and becomes the reservoir for the 
fecundating corpuscles. That of the female group, on the contrary, 
gradually disappears. 
The colouring of the two groups is also very different. The 
female elements remain colourless, while the males cells are either 
yellow or green. 
The contents of these cells become converted into a number of 
small daughter-cells, furnished with a membrane and a nucleus. 
These daughter-cells are after awhile replaced by innumerable small 
dark corpuscles, much resembling minute Ameebe, but their form 
does not change. The large mother-cells lose their colour and 
transparency, and break up into a sort of powder. In many cases the 
Ameboid corpuscles undergo a further evolution into “ small un- 
equal bacilli, which are straight or diversely flexuose, immobile and 
colourless.” We might, he adds, “ easily be led to regard them as a 
parasitic vegetable production, if we had not before our eyes all 
the successive phases of the transformation of these elements.” 
In addition to which he adds that they are readily soluble in 
alkaline fluids. 
It would be a mistake to suppose that the process now described 
by Balbiani as the male generative organ has altogether escaped 
earlier observers. It was observed both by Huxley and Leydig, as 
indeed Balbiani points out, but was regarded as a pseudo-vitellus. 
I myself had observed a mass of small green cells in the pseudovum 
of Coccus,* but I regarded them as parasitic vegetable cells, and, as 
we have seen, the same idea occurred independently to M. Balbiani, 
but was not adopted by him for the reasons already given. My 
“green cells,” however, do not correspond with the “ pseudo- 
* “On the Ova and Pseudova of Insects,” Phil. Trans, 1859, pp. 362, 363. 
