DYNAMICS OF MORPHOGENESIS 



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soon as cut were placed in water at room temperature, 18° to 22°C. 

 and allowed to regulate there. Similar lots of fifty pieces each 

 were cut at 10° to 12°C. and then kept in water of the same tem- 

 perature during regulation. The series is then a comparison of the 

 character of regulation at two different temperatures of pieces of 

 animals kept at the lower of the two temperatures before operation. 



Table 6 gives the results in percentages: // 1 a-d are the 

 pieces which regulate at the higher temperature, 18° to 22°C. and 

 II 2 a-e those which regulate at 10° to 12.° 



In II 1 regulation was complete in less than two weeks and the 

 pieces were examined on January 7, 1912: in // 2, on the other 



hand, regulation was not completed before February 1. In this 

 series, as in the KCN series, 432 above, the three pieces a, b and 

 c are almost always within the first zooid while d almost always 

 consists in large part of the anterior region of the second zooid. 

 At both temperatures the characteristic axial gradient appears, 

 as table 6 shows. The regulatory capacity decreases from a to 

 c and increases again in d. But comparison of the results at the 

 two temperatures shows first that the pieces at the higher tempera- 

 ture possess a much greater regulatory capacity than those at 

 low temperature, and second, that the effect of the temperature 

 differs in pieces from different levels. In the a-pieces 62 per cent 

 are changed by the higher temperature from teratophthalmic to 

 normal: in the 6-pieces the difference is still greater, for at the 

 higher temperature 56 per cent are normal and 100 per cent form 



