No.1.] BUDDING [N GOODSIRIA AND PEROPHORA. 199 
in this connection it is significant that the resemblance of the 
Anlage cells to the mesenchyme cells does not apply to a// the 
mesenchyme, or blood cells by any means. Asa matter of fact, 
it is to a comparatively small number of these latter that the 
former have such a resemblance.) 
A detailed account of the development of the heart from the 
pericardial vesicle is just as little necessary here as in the case 
of Goodstria, where it was stated that such a description would 
be superfluous, so entirely does the process correspond with 
what has been many times described for other Tunicates. Fig. 
61, Az., Pl. XVI, incidentally shows the heart beginning to 
form by an invagination of the large pericardial vesicle. 
The matter of chief interest in connection with the develop- 
ment of the heart in the buds of Pevophora remains to be 
considered. I refer to its azrect origin from the primitive 
inner vesicle, and its consequent independence of the stolonic 
septum. The facts in relation to the subject were partly pre- 
sented, as will be recognized, in describing the manner of 
attachment of the blastozooid to the septum; and the whole 
question might have been very properly discussed there. 
But, since it has been more commonly treated in connection 
with the heart by other authors, it seemed best to adopt the 
same plan in this instance. It has already been pointed out 
that Van Beneden et Julin supposed Clavelina and Perophora to 
agree in this respect, as they do in many others. In order to 
make it clear that they do not, it will be necessary to point 
out what, according to these authors, are the conditions in 
Clavelina. An understanding of them in all their details can 
hardly be reached, however, without aid of the numerous fig- 
ures by which the authors have illustrated the subject. These 
are all the figures of plate XI; figures 1 to 7, plate XV; and 
figures 3%, 35, 3°, 34, and 3¢ of plate XVI of their well-known 
memoir ('87). 
The parts essential to an adequate understanding of the 
conditions described by them are: the primitive inner vesicle, 
the branchial sac, the “tube épicardique,” the “sac épicar- 
dique,”’ and the “cloison stoloniale.”’ 
To make the subject clear, and at the same time to do so as 
