CHAIN OF CYCLOSALPA AFFINIS 431 
number one. Further there is no opportunity in the Pyrosoma 
group for the differential mechanical action caused in Cyclosalpa 
by the growth and crowding of the zooids while the foot-pieces 
diminish in size. Neither is it possible seemingly, for the periodic 
phenomenon to play any such part in the arrangement ofthe 
Pyrosoma zooids as it appears to in Cyclosalpa. 
THE LARGER SIGNIFICANCE OF SUCH STUDIES 
1. Supplementing biological with quantitative observations 
We venture to call attention to the way in which morphological 
and physiological observations and considerations join hands 
with quantitative observations in this research. Numerous 
structural details in the adult individuals of both sexual and 
asexual generations, in the chain of zooids as a whole, in the in- 
dividual wheels and the individual zooids composing the wheels, 
and in the unbroken part of the chain both as a whole and as to 
its individual elements had to be attended to. On the functional 
side not only growth in several of its aspects, but the mode of 
swimming, certain facts pertaining to the circulation of the blood, 
and some points about nutrition have come in for consideration. 
All this sort of thing is so familiar to modern biologists as to 
need no special mention. Not so with what we have done in a 
quantitative way. It seems to us that in this we have entered 
a region of research that biologists will be compelled to regard 
vastly more seriously in the future than they have in the past or 
do now. The case in hand furnishes a rather striking illustra- 
tion of what the quantitative method can do. It can enable us 
to see facts we cannot see otherwise. It amounts to a great 
increase in the power of our eyes just as does the microscope. 
This statement is to be taken literally, not figuratively. One 
may easily imagine a magnifying instrument that would so en- 
large the wheels as to make visible the size differences between the 
zooids. It would seem that this is what the application of math- 
ematics in physical science very frequently does. We should 
never have suspected from ordinary examination size differences 
