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 



