No.1.] BUDDING IN GOODSIRIA AND PEROPHORA. 201 
épicarde, en avant péricarde et cloison stoloniale en arriére.”’ 
And on another page they show that the cavity of the fev7- 
cardium ts directly continuous into the virtual lumen of the 
clotson, and that this is the condition retained in the adult 
zooids. 
The essential facts here set forth, summed up in the fewest 
words possible, are these: The epicardium is derived from the 
branchial sac, or more precisely from the part of the primitive 
inner vesicle that later forms the branchial sac. The peri- 
cardium is derived from the epicardium. The epicardium 
remains in connection with the branchial sac, but becomes 
fully separated from the pericardium. The pericardium re- 
mains in connection with the cloison. 
That the epicardium is a well-defined structure in Clavelina, 
is obvious from the description and figures of it by the authors. 
Thus it communicates with the branchial sac by two openings 
called by them “orifice épicardique,” these being in reality 
two short tubes passing between the branchial sac and the 
“tube épicardique”’ proper, which is a single wide cavity 
terminating posteriorly in two “cul-de-sacs épicardiques.” 
That the course of things in Perophora is very different from 
this is clearly seen by an examination of the series of Figs. 60, 
61, and 62, Pl. XVI. The most striking difference is in the fact 
that in Perophora the pericardium nezther at its origin, nor at 
any later time, has any connection whatever with the cloison of the 
stolon; see particularly Fig. 70, Pl. XVI, from another some- 
what younger bud. From these it is seen that it arises directly 
from the primitive inner vesicle on its rzgh¢ side, consequently 
remote from the point of attachment of the cloison to the 
inner vesicle, which point is on its 4f¢ side, corresponding in 
this stage of development to the posterior extremity of the 
left peribranchial sac. This difference implies the further one 
that there ts no epicardium in Perophora, at any rate holding 
such a relation to the pericardium as this structure does in 
Clavelina. It may be asked if the portion of the primitive 
vesicle from which the pericardium is derived may not be 
regarded as representing the epicardium of Clavelina. It 
certainly does hold the same relation to the inner vesicle; z.e. 
