DEVELOPMENT OF THE CAPE SPEOIES OF PERIPATUS. 179 
Tur SEGMENTATION. 
The general features of the segmentation have already been 
described in Part 1 (this Journal, vol. xxv). 
The first furrow passes through the centre of the opaque 
patch, and at right angles to the long axis of the ovum. Each 
of the two segments resulting from this consists of a small 
Opaque portion, which contains the nucleus and is closely 
applied to the opaque part of the other segments (Part 1, fig. 4). 
A careful examination of this ovum shows that the furrow has 
not completely separated the two segments from each other, 
but that they are connected by strands of protoplasm forming 
a loose network between them. This network is simply a 
looser part of the ordinary protoplasmic network described at 
* the beginning of this article. There are, however, no such 
strands between the most superficial parts of the opaque area; 
in this region the furrow is for the moment complete. Soon, 
however, the clearer protoplasm (where the network is looser 
and continued into the still looser network between the two 
segments) extends upwards on the inside of the dark patch, so 
that when four segments are formed by the second vertical 
furrow each dark patch is surrounded on all sides by a layer of 
the looser reticulum (Part 1, Pl. XXXI, fig. 5), which is here 
as elsewhere continucus with the reticulum of the adjoining 
segments. 
Two changes now occur: (1) the pale, clearer, and larger 
part of the four segments begins to break up into smaller, 
irregular masses of varying size, which, however, are seen on 
careful examination to be connected with each other by a wide- 
meshed reticulum, and (2) a third furrow appears dividing the 
four dark patches, which I have called the ectoderm cells, into 
eight patches or cells (Part 1, fig. 7). This furrow may be 
looked upon as corresponding to the horizontal furrow, which 
ordinarily follows the second vertical furrow in the segmenta- 
tion of the ovum. The ovum therefore now consists of eight 
ectoderm cells, and four large and a number of smaller endo- 
derm masses, all connected together by a wide-meshed reticulum, 
