No.1.] BUDDING IN GOODSIRIA AND PEROPHORA. 221 
be confined to a single row on each side of the endostyle, and 
not far from it. 
PEROPHORA ANNECTENS. 
1. The inner or endodermic vesicle of the bud is derived 
from the stolonic septum; and from this are derived the 
branchial and peribranchial sacs, and the digestive tract in a 
manner in all essentials similar to that of all other Ascidian 
buds. 
2. The peribranchial sacs of the developing blastozooid are 
formed in such a manner that the stolonic septum is connected 
to the left one of these, and not to the branchial sac, as has 
been hitherto supposed. 
3. The pericardial Az/age arises almost certainly from the 
wall of the inner vesicle, though there remains some doubt 
whether or not it may be produced by an aggregation of 
mesenchyme cells. But if this is so it is still probable that its 
ultimate source is the endoderm, since the mesenchyme cells 
that seem to enter into it are themselves probably produced 
by the endoderm. 
4. The ganglio-hypophyseal Az/age was originally produced 
from the endodermic vesicle as an evagination, as it is in the 
buds of numerous other Ascidians. This primitive method of 
origin is, however, found in an occasional individual only at 
the present time, the evagination having, in most cases, been 
replaced by a migration of cells. 
For the most part this migration takes place at the point at 
which the ganglion will be ultimately situated; but it may 
occur at other points more or less remote from this, and the 
coming together of these migrating cells makes it appear as 
though the Az/age is produced from mesenchyme cells. Or, 
as in the case of the pericardial Az/age, we may consider that 
mesenchyme cells do participate in the formation of the Ax/age, 
but that these cells are derived from the endodermic vesicle. 
