NOGUCH 



PLATE 30 



I to 4. Eggs of Arbacia punctulata. I, Normal. 2 to 4, Different stages of 



Ovolysis caused by 1 per cent Cobra venom in sea-water. 



5 to 8, Eggs of Lepidonatus squamatus. 5, Normal. 6 and 7, Different stages 



of Ovolysis caused by I per cent Cobra and 2 per cent Crotalus venom, 

 showing no real Ovolysis, but peculiar Retraction of Deutoplasm. 



9 to 11. Pluteus stage of Arbacia punctulata. 9, Normal, active pluteus. 10, Plu- 

 teus under the effect of 2 per cent Cobra venom. I 1, Disintegration 



under the effect of same venom. 



f_-Tawings by Noguchi.) 



