218 RITTER. [Vou XI1. 
In Clavelina, Distaplia, Glossophorum, and Fragroides the 
epicardium gives origin either directly or through the stolonic 
septum to the inner vesicle, or endoderm, of the bud. In 
Botryllus and Goodsiria the so-called epicardial sacs have noth- 
ing whatever to do with the budding, and there is not the 
slightest evidence that they ever had anything to do with the 
process. The last part of this statement is at least true for 
Goodsiria. Here the buds arise, as reference to Figs. 9 and Io, 
Pl. XII, will show, far forward on the parent zooids, while the 
epicardial pouches are at the extreme posterior end of the 
animal. All they are is this: When the intestine begins to 
form at the postero-ventral side of the primitive inner vesicle 
it produces, as one might say, an obstacle in the way of the 
further expansion posteriorward of the inner vesicle, which, of 
course, is constantly growing. The notch thus produced 
has been already described, and is well seen in Fig. 16, d., 
Pei: 
The extensions of the vesicle on each side of this notch are 
the epicardial sacs of the adult animal. When the peribranchial 
sacs are completely formed the epicardial sacs are merely their 
posterior extremities. 
And now a word concerning the relation of the epicardium 
to the heart. In attempting to show that the epicardium is 
the same structure in all Tunicates, and to make use of it asa 
basis for classifying the group, Garstang has tried to escape 
the difficulty of its being in some cases connected with the 
heart, while in other cases it is not, by supposing that such 
connection is secondary. 
In my account of the origin of the heart in Goodszrza I have 
shown that it arises from the right epicardial pouch, and I 
can certainly see no reason for regarding this method of origin 
as secondary. In fact, it was partly this consideration that 
made me speak of the pouch as an epicardium in my preliminary 
communication. 
Concerning the epicardium in Pevrophora, after describing 
the relation of the bud to the stolon, I have said in my prelim- 
inary paper: “It is obvious that there cannot be in Perophora 
an epicardium corresponding to the structure called by that 
