Following results were obtained with fertilized frog eggs. (1) The cleavage delays at 500 kg/c㎡ and stops at higher pressure than 1000 atm. (2) The cleavage furrow becomes irregular and deep at 300500 kg/c㎡. (3) Abnormal tadpole often developes from compressed fertilized eggs. (4) It is supposed that jelly layer of frog eggs is also affected by high pressure.