EARLY DEVELOPMENT OF JULUS TERRESTRIS. 4.53 
matin granules which are present in small numbers (fig. 15). 
Within the deeply staining nucleolus, several vesicular spaces are 
present. I am unfortunately unable to read Russian, but from 
an examination of the figures of a Russian paper by Repiakoff, 
published in 1883, on the development of Geophilus, I imagine 
that the ovum of Geophilus at this stage is of similar structure. 
I have been unable to observe anytiing of the impregnation 
of the ova, which probably takes place immediately before 
deposition. 
My earliest stages occur late on the same day on which the 
ova are laid; sections through such ova show (fig. 3) that the 
protoplasmic network and yolk-spherules remain as before, but 
the nucleus is no longer at the periphery, but is situated in a 
mass of protoplasm in the centre of the ovum. This mass of 
protoplasm is of irregular shape, but its long axis corresponds 
with that of the ovum. From it ameeba-like processes radiate 
in all directions, forming a protoplasmic network throughout 
the egg (fig. 17, a, 6). The nucleus is no longer a distinct 
vesicle, but its position is marked by the chromatin granules 
alone. There is no nucleolus. 
Early on the second day the nucleus and the central mass of 
protoplasm divide into two parts. The division of the proto- 
plasm is not, however, complete, the two resulting masses with 
their nuclei remaining connected by a network of protoplasm. 
This is shown in figs. 4 and 16. The two first segmentation 
masses separate till they are some distance apart, though still 
connected by strands of protoplasm ; they then divide, so that 
we now have four segments all connected together. This pro- 
cess is carried on until there are a considerable number of 
these segmentation masses present, and early on the third day 
the first formation of the blastoderm begins. At the close of 
segmentation the ovum consists of a number of these segmenta- 
tion masses, resulting from the division of the original central 
mass of protoplasm. Each of these masses has a dense central 
portion, in which is situate the nucleus, while the outer portion 
is broken up into innumerable processes, which connect the 
masses together and permeate the yolk in every direction. 
