SUSCEPTIBILITY OF AMPHIBIAN OVA TO X-RAYS 



483 



Experiment B 



Experimeyit D 



Blastopore closed at time of irradiation. 



Neural groove visible in most specimens at time of Irradiation. 



Distinct larval form In most specimens at time of Irradiation. 



Experiment E 



All appeared to develop normally but none were kept and fol- 

 lowed through metamorphosis. 



Head and tail anlages well marked at time of irradiation. One 

 died before metamorphosis. Cause? 



Irradiation just before hatching. All died before metamorpho- 

 sis but cause apparently not irradiation. 



THE AMERICAN JOURNAL OP ANATOMT, VOL. 11, NO. 4. 



