Juxy 14, 1899.] 
To sum up, the general result indicates 
that the opinions regarding the aster-forma- 
tion referred to above can in a measure 
be reconciled. In the case of echinoderm- 
Fic. 4.—Section of sea-urchin egg (Toxopneustes), 
13 minutes after entrance of the spermatozodn, show- 
ing sperm-nucleus, middle piece and aster (about 
2,000 diameters). 
eggs Butschli and Erlanger correctly de- 
scribe the aster as involving a radial ar- 
rangement of the alveoli, but they have 
failed to recognize the fibrillee that lie be- 
tween them, and Boveri is, therefore, thor- 
oughly justified in the contention that the 
astral systems cannot be regarded as merely 
a radial configuration of the preexisting 
meshwork. I, nevertheless, think that Hert- 
wig, Reinke and myself were right in the 
contention, which has been made also by 
many others, that the rays grow by pro- 
gressive differentiation out of the general 
cytoplasmic meshwork, and that there is no 
ground, in the echinoderm-egg at least, for 
the recognition of a specific ‘archoplasm ’ 
or ‘ kynoplasm’ from which they arise. 
SCIENCE. 41 
Finer Structure and Origin of the Meshwork. 
—We may now consider what is, I think, 
the most suggestive of the questions pro- 
pounded, namely, that relating to the finer 
structure and origin of the 
mesh work. We have thus far 
distinguished sharply between 
alveolar spheres, granules, or 
microsomes, and continuous 
substance. Morphologically con- 
sidered, however, there is good 
reason for the view that all 
these are but different grada- 
tions of one structure. In the 
first place a nearly or quite com- 
plete series of size gradations 
exists between the largest alve- 
oli and the microsomes (Fig. 1, 
b,c). Although most of the 
alveoli vary but slightly in size 
from the mean, a little search 
shows the presence of many 
smaller ones, and here and there 
they seem almost, if not quite, 
as small as the larger micro- 
somes. In thesecond place, careful study of 
the‘ continuous’ substance in life, especially 
in the crushed protoplasm, shows that the 
larger microsomes in turn graduate down 
to granules so small as to lie near or at the 
limit of microscopical vision. The ‘ con- 
tinuous’ substance is, in other words, filled 
with granules, 7. e., drops of all sizes, rang- 
ing from the smallest visible ones up to the 
largest alveoli. It is this fact which Mrs. 
Andrews, as I understand her statements, 
has in view in maintaining that the coarser 
alveolar structure ‘‘is not, indeed, the final 
structure of the living substance, but is 
part only of an infinitely graded series of 
vesiculations of the protoplasmic form ”’ 
and with this statement I entirely agree. 
But we cannot stop here. Irresistibly 
the further question suggests itself: 
Why should we place the end of this 
series at the end of microscopical vision 
