90 ME. LUBBOCK’S ACCOTJKT OE THE TWO METHODS OP EEPEODUCTIOX 
cases where none was present, I have seen agamic eggs beginning quite at the posterior 
part of the ovary. 
The mode of formation is as follows : — we have seen that the brown darkening or first 
stage of the ephippial egg [c) commences round one of the cells, which therefore is 
doubtless a germinal vesicle. Exactly similar cells and similar ovarian masses occupy 
also the anterior part of the ovary. See Plate VI. figs. 1 and 2. 
One of the cells in one or more of the ovarian masses becomes shghtly enlarged, so as 
to measure about '002 in diameter, and round it, inside the cell, are deposited several dark 
granules, and little oil-globules'* ; the process being the same as in the formation of the 
ephippial egg, with the addition of the oil-globules. This process may be going on only 
round one cell or round several at once, as in Plate VI. fig. 3, and the embryonic eggs agree 
j)recisely with Dr. Maetin Baery’s descriptions and figures of eggs of Vertebrata in a 
similar condition f. The two sides of the animal do not always present the same appearance, 
though they seem to have a tendency to do so. At first two or even three other ovarian 
cells may be seerr in the same ovarian masses, but there never appears to be any tendency 
to development rourrd more than one of them. The others, and the wall of the ovarian 
rrrass itself, appear to fade away, leaving the ovule to consist orrly of the germrinal vesicle, 
grairrrles and oil-globules. These two latter in the meanwhile increase, and the globules 
become larger and more numerous ; the germinal vesicle becomes much less distinct, pro- 
bably being concealed by the surrounding matter. This is, however, very difficrrlt to 
determine, because the ovules having now no enveloping mernbraire, and the component 
parts rrot beirrg so firmly kept together by teiracious gelatinous substance, as Dr. Nelsox 
has observed in Ascaris mystax, it is almost impossible to extract them Aom the ovary in 
anything like a perfect state. In some cases this deposition of granules and globules 
seemed not to take place round any germinal vesicle, but this I believe is a deception 
caused by a transverse position of the ovule to the ovary. 
As the process of development continues, the ovary-walls begin to be pushed out here 
and there by the germ-matter, which accumulates in front, and the eggs clothe themselves 
with an extremely elastic and at first very delicate skin, the \itelhne membrane, wlrich 
does not acquire its full consistency until it has been some time in the receptacle. 
The eggs sometimes, after being developed to a certain extent, fade away agam and 
disappear. But these are exceptional cases. I have only seen tlrree or four, although I have 
Avatched the process of development so often. These fcAv also appeared to be connected 
AAith weakness or disease, for in two of them the animals died soon after, and therefore 
the phenomenon cannot be compared with the disappearance of the incipient ephippial 
egg, AAliich is the rule and not the exception, and takes place even when the animal is in 
excellent health. 
* I call them oil-globules merely on account of their appearance. 
t See Philosophical Transactions, 1838, Plate V., where there are many cases of embryonic eggs figm’ed 
as consisting like those in Plate VI. fig. 3, of an outer cell, which afterwards disappears, of a germinal vesicle, 
oil-globules, and dark granules. 
