2 



forms, iilastulap and Dlanulae ranpjinR in aRe froT five to 

 twenty-seven hours v/ero prese.ved and sectioned for *.ho 

 study of the various stages in t.ho formation of the enXoderm 

 and the other features of develOT:ment which tna]:e thoir ap- 

 Dearanci dUx-infC this period, 



I v.'ish to acknowledge my obligations to ohe Honorable 

 George M. Bov/ers, Commissioner of Fisheries for the privoleges 

 afiorded me at the Fisheries Laboratory; and also to thank 

 Dr. Caswell Grave, Director of the Laboratory for helo and 

 sug^:estions. The v.'ork -vas finished in .he Biological Lab- 

 oratory of the Johns Hopkins University. For the interest 

 shovm and for kind suggestions offered during my work I am 

 very grateful to Professor V;. K. Brooks. 

 DLHISCZLCS. 



The eg 's are discharge^.! at about five o'clock in the 

 morning. The ectod^:r;:ial eDitholiun of the ovaries becomes 

 ruptured, in fac*. broken down; and by the movements due to 

 the muscular contractions of ihc nanubrium the egrs are sot 

 free into the cavity of the sub-u.nbrella. Then by the rhyth- 

 mic contractions of the bell they arc- forced out of the bell 

 cavity into the v/ater outside. V/hile the eg^s ai?o being 



