No.1.] BUDDING [N GOODSIRIA AND PEROPHORA. 215 
the one just pointed out is this: in Goodszria it would always 
be the mother ascidiozooid that would be attached to the 
stolonic septum by its peribranchial sac, while in Perophora it 
is the daughter zooid that is so attached. Or, to express the 
same thing in another way, we do not know how any given 
blastozooid of Goodstria would be attached to the supposed 
stolon from which it would arise. We only know how it would 
be attached to the stolon that would arise from 7¢. 
In reality, then, there is a rather deep-seated difference 
between the processes in the two genera. I am, however, far 
from affirming that the difference is fundamental. It is not at 
all impossible that they may be modifications, though rather 
profound ones, of a common original process. How is the 
question to be decided? The answer I wish to give with 
emphasis. If it is ever to be correctly answered, it must be 
by considering the evidence afforded by the d/astogenesis in 
connection with the evidence to be derived from embryogenesis 
and from the comparative anatomy of the adults. 
It was my original plan to make the discussion of the ques- 
tion as full as the data at hand would permit ; and with this in 
view I have already prepared the manuscript for the anatomical 
comparison, and in fact have presented it in brief on another 
occasion. Further reflection has, however, convinced me that 
it will be better not to attempt a full description until the 
embryological data for both genera, now almost wholly wanting, 
have been furnished. We must know how the peribranchial 
sacs arise in the embryo in each case, and also how the first 
bud arises in each case, before we have a basis on which to 
profitably speculate. 
It will be worth while to point out briefly how unsatisfactory 
such speculation would of necessity be in view of our imperfect 
knowledge of the ontogeny in these genera. 
We have no observations on the origin of the peribranchial 
sacs in the embryo of either Perophora or Goodsiria. Neither 
do we know how the first bud arises in either case. We might 
infer that in these particulars Pevophora is like Clavelina ; in 
fact, such an assumption is generally made. But as I have 
shown the relation of the blastozooids to the stolon to be very 
