Nor3.| BUDDING IN PEROPHORA. 407 
of free amoeboid cells in the body cavity. Such is the origin, 
for instance, of the nervous system and pericardium, which, 
however, in the embryo are respectively ectodermal and endo- 
dermal structures. 
Since in the development of the bud and that of the larva 
the same end is reached by entirely different roads, and in the 
former organs do not proceed from corresponding larval organs 
or even their germ-layers, and, moreover, since in the bud a 
rudiment derived from one and the same embryonic germ-layer 
may give rise to structures of widely different nature, one is 
compelled to believe with Hjort that «die Knospung der zusam- 
men gesetzten Ascidien ein Entwicklungsprocess ist, in welchem 
samtliche Organe durch ‘ Neubildung’ aus einer sehr primitiven 
Anlace -entstehen . 2.6: “Die Knospe: muss ihre: eieencn 
Gesetze haben und muss, da sie aus einer wesentlich anderen 
Anlage hervorgeht als die Larve, auf andere Weise gebildet 
werden. Ebenso wie das Ei, muss das Material, die Anlage, 
welche den Ausgangspunkt fiir die Entwicklung bildet, als ganz 
undifferenzirt gedacht werden und muss alles enthalten, was zur 
Bildung eines ganzen Individuums notig ist, ebenso wie die 
Blastula des Eies”’ (9; p. 225). 
The behavior of the blood cells in the bud development of 
Perophora viridis is of much interest, owing to the number and 
variety of organs in whose formation they are concerned. As 
we have seen, these cells give rise to the pericardium, the dorsal 
tube, the ganglion, and the sexual organs; they also produce 
the musculature, and, as Kowalewsky (14) and Seeliger (32) 
have shown in other ascidians, in Perophora also they doubtless 
become the cells of the cellulose test. 
As I have repeatedly emphasized in describing the formation 
of the various organs in question, there is not the slightest 
discoverable evidence that cells are given off from the wall of 
the vesicle at the places where such organs arise, or at any 
other point, for that matter, and the similarity between the cells 
which make up the different rudiments and the free amoeboid 
cells of the blood is so perfectly apparent, especially at early 
stages, that the two are certainly identical. 
The origin of these blood cells must, however, be left in 
