464 F. G. HEATHCOTE. 
The above is a short account of the early literature of 
Chilognath development in the first stages of development, and 
as with the exception of Metschnikoff’s paper the only bearing 
they have on my own work is to show that Chilognatha, even 
in very closely allied species, are hatched at different stages 
of development, I shall not refer to them again, with the 
exception of Metschnikoff’s paper, which I shall mention 
further in the next section of my paper when discussing the 
bearing of my own work. 
Summary. 
With regard to the segmentation I have described, it will be 
seen that it differs considerably from that seen by Metschni- 
koff (9), who describes it as total; the ovum being divided 
into two, four, &c., segments. I saw nothing of such a divi- 
sion, nor does Newport, who observed the eggs of the same 
species as I did, record any such appearances. Newport’s 
observations were made on the eggs of a species found in 
Madeira; that is in a hot climate; and as regards segmen- 
tation were not carried on by means of sections. As the 
amount and distribution of the food-yolk has a great influence 
on the segmentation, I think it probable that in my species 
the segmentation differs slightly from that in the species 
investigated by Metschnikoff. The difference, however, con- 
sisting in the external segmentation of the ovum is not, I 
think, a very important one. The segmentation of Julus 
terrestris, as I have described it, shows a remarkable re- 
semblance to that found in Amphipods by Ulianin (14). He 
describes an external segmentation by means of shallow 
furrows formed in the surface of the ovum, which is composed 
in great part of food-yolk; in each space thus marked out, a 
large ameeba-like mass of protoplasm provided with a nucleus 
is present ; the division of these protoplasmic masses coincides 
with the formation of the furrows. When the blastoderm is 
just about to be formed the furrows disappear. At the close 
of segmentation, then the ovum is exactly like the ovum of 
