No.1.] BUDDING [IN GOODSIRIA AND PEROPHORA. 179 
was, however, based on indirect and theoretical grounds, viz. : 
on the facts that in its earliest stages the constituent cells 
much resemble those of the mesoderm by which it is sur- 
rounded ; that no other source for them was observed which 
appeared more probable ; and that in the embryonal develop- 
ment a portion of the dorsal nerve undergoes dissolution, its 
cells becoming transformed into the free mesoderm cells. It 
was conjectured that these latter might reassemble again to 
form the ganglion of the bud. But this view has, I believe, been 
given up by the author. The belief in a common mesodermal 
origin of hypophysis and ganglion, as described by Seeliger 
(89), in the buds of Pyrosoma, appears to rest on a much 
securer foundation. Very recently Lefevre (95) has main- 
tained such an origin for the ganglion in Perophora. 
In Goodsiria, the very early stage at which the ganglion is 
found to be fully separated from the hypophyseal duct, together 
with the conditions which I have observed. in Perophora, have 
induced me to look for evidence of its mesodermal origin here. 
The close resemblance of its cells in its early stages to certain 
of the surrounding cells in the body space, z.e. mesenchyme cells, 
and the difficulty of observing its origin from any other source, 
are the only facts that lend any countenance to such a view — 
facts certainly of little weight, particularly when opposed to 
direct evidence of a contrary kind. What I shall have to 
say on this point when treating the gangleo-hypophyseal 
development in Pevophora will be of greater moment. 
The ectodermal origin of the ganglion in the bud has 
been asserted by Van Beneden et Julin (87), for Clavelina ; 
by Oka (92), for Lotryllus ; by Salensky (92), for Pyrosoma ,; 
and by Brooks (93), for Sada. Of these authors’ works 
the most important for us in the present connection is 
that of Oka. This is most important because of the obvi- 
ously close relation between Botryllus and Goodsiria ; because 
of the positiveness of the author; and because the work 
is very recent, and consequently was done by methods in 
common use at the present time, and in the light of pre- 
vailing theoretical views. It must, therefore, be examined 
critically. The author first describes and figures an irregular 
