nionema ) , The Ronad thus becomes an elongated ridge of 

 tissue which finally reaches to the extremities of the 

 chimiferous tubes, and increases in depth until it hangs 

 down into the subumbrella as a ribbon. Early in its devel- 

 opment the ribbon is somewhat sinuous, and as the medusa 

 attains greater diameter the convolutions become more ne- 

 merous and farther extended on either side of the radial 

 canal, until ultimately the folds are packed tightly to- 

 gether in a solid band of tissue, which at the time of ma- 

 turity is extended with sexual elements. The process of 

 formation of the sexual organs is identical in the two sex- 

 es; it is impossible to tell whether a given individual is 

 male or female until the sexual products begin to mature. 



