ALTERNATE GENERATIONS. 253 
join it just at the point where the eyes are 
placed, so that the extremity of each tube 
unites with the base of each eye. Those parts 
of the margin filling the spaces between the 
eyes correspond to the depressions dividing the 
lobes or scallops in the earlier stage, and to 
these radiate the eight other tubes alternating 
with the eye-tubes, now divided into numerous 
branches. Along each of these spaces is devel- 
oped a fine, delicate fringe of tentacles, hanging 
down like a veil when the animal is at rest, or 
swept back when it is in motion. In the previous 
stage, the tubes ramified toward the margin ; but 
now they branch at or near their point of starting 
from the central cavity, so extensively that every 
part of the body is traversed by these collateral 
tubes, and when one looks down at it from above 
through the gelatinous transparent disk, the nu- 
merous ramifications’ resemble the fine fibrous 
structure of a leaf with its net-work of nervules. 
On the lower side, or what I have called in a 
previous chapter the oral region of the animal, a 
wonderfully complicated aparatus is developed. 
The mouth projects in four angles, and at each 
such angle a curtain arises, stretching outwardly, 
and sometimes extending as far as the margin. 
These curtains are fringed and folded on the 
lower edge, so that they look like four ruffled 
flounces hanging from the lower side of the 
