1912] Torrey: Oxygen and Polarity in Tubularia 251 
sixth proximal hydranth had emerged and a seventh was emerg- 
ing. In the same dish, sixteen hours later, all nine proximal 
hydranths were out, but still no distals; nor did distals show any 
sign of developing in the de-oxygenated water for two days 
longer, when the experiment terminated. The control pieces 
ultimately developed nine distal and seven proximal hydranths, 
two failing to develop proximally. 
It is obvious from these brief records that not only was lack 
of oxygen hindering the development of the distal hydranths in 
one set of stems, but the proximal ends of these stems were 
developing more rapidly in consequence; and this when all pos- 
sible influence of ligatures or contact stimuli had been removed. 
Transmitted April 22, 1912. 
LITERATURE CITED 
Logs, J. 
1904. Concerning dynamic conditions which contribute toward the 
determination of the morphological polarity of organisms. 
Univ. Calif. Publ. Physiol., 1, 151-161, 7 figs. in text. 
1906. The dynamies of living matter (New York, The Columbia Uni- 
versity Press), vi + 233, 64 figs. in text. 
Torrey, H. B. 
1910. Biological studies on Corymorpha. IV. Budding and fission in 
heteromorphie pieces and the control of polarity. Biol. Bull., 
19, 280-801, 18 figs. in text. 
