LIFE-HISTORY OF CRASPEDACUSTA RYDERI. 



435 



To my surprise I had both sexes and many developing eggs. A 

 week later a second collection from the same place was made by 

 Mr. Giovannoli and brought to Bloomington. They were 

 collected and brought to Bloomington the same day, hence they 

 reached me in good condition. From this lot I was able to work 

 out most of the essential stages in the development of the egg 



into the hydroid. 



DEVELOPMENT. 



No attempt was made to make a detailed study of the develop- 

 mental stages, but sufficient work was done to give the main 

 trend of events. 



FIGS, i, 2, 3, AND 4. Sections of some early cleavage stages; 4, a ciliated 

 blastula. 



The germ cells lie in the ectoderm of the gonads, which hang 

 as sack-like pouches from the radial canals. In the ovaries the 



