G. REVERBERI 327 



Fig. 2. Phalhisia tadpoles, a, controls; b, treatment with O.lAf sodium 

 azide for 3 hours before fertilization, and development in O.OOlAf azide; 

 c, treatment as in b, interrupted at neurula stage. 



Fertilized eggs can develop only in dilute solutions (from 2 X 

 10~^ M); the CO. is only partially inhibited. The developed tad- 

 poles possess normal "head" with brain, sensorial spots, and palps, 

 but very abnormal tails (Fig. 3). The same results are also ob- 

 tained when the treatment was interrupted before the differentia- 

 tion of the musculature, that is, at the neurula stage (Fig. 2c). 



Treatment with Malonate. Development is affected only at 

 concentrations about 5 X 10~- M or stronger. In Fig. 4 are pre- 



f 









^ ^^J 



f: 



k 



• f 





Fig. 3. Phallusia tadpoles, a, controls; b, development in 2 X 10 ~^ M 

 sodium azide; c, development in 3 X 10~^ M azide. 



