No.1.] BUDDING IN GOODSIRIA AND PEROPHORA. 185 
from their parents. Do these latter zooids remain throughout 
their lives incapable of sexual reproduction ; or do they receive 
their ova from the blood vessels with which, as previously 
shown, the zooids become secondarily connected; or have some 
of the cells contained in the blood the capability of being 
transformed into sexual cells; or finally, are the sexual cells 
really brought into the bud from the parent, which again re- 
ceived them in the same way from its parent, and so on till 
their ultimate origin was the sexually produced common an- 
cestor of the entire colony? The last is, I suppose, the alter- 
native that would appear most probable to the great majority 
of embryologists, since it is the one most in conformity with 
prevailing theoretical views concerning the origin of the repro- 
ductive elements. It is also in keeping with the early appear- 
ance of the sex cells in the Sa/pa stolon, as made known by 
Kowalensky, Salensky, Brooks, Seeliger, and others; also with 
what occurs in the budding of Pyrosoma. 
But most of all it is supported by the conditions presented 
by the buds of Botryllus. The large ova in the young buds of 
this species, known since the time of Savigny (16), have by 
many writers been supposed not to appear in any of the buds 
before the third or fourth generation. Pizon (93), has, how- 
ever, shown that they really originate in the sexually produced 
embryo, and migrate, as he expresses it, through the first 
generations of buds, leaving these to develop into sterile zooids, 
only to become permanently fixed as ovaries in later genera- 
tions. 
The fact that I have not been able to distinguish sexual 
cells among the blood cells in the young buds of Goodstria 
may not be regarded as proof that they do not exist there. 
They may be in so early a stage of differentiation that, with 
the methods of preservation and staining employed, their 
distinguishing characters were not brought out, as they might 
have been by some other treatment. 
It is true that I have occasionally found large polynuclear 
cells (Fig. 55, Pl. XVI) that have seemed to me to be possibly 
the forerunner of the cell aggregates. These I have again 
conjectured to be a stage in the formation of the polycarps. 
