THEORY OF AXIAL GRADIENTS 



271 



TABLE 4 



Time in hours required for emergence of the oral hydranths in pieces of different 



length 



Ratio of the length of the pieces = 1:3. 



Series A Apical piece = 10 mm. Basal piece = 30 mm. 



Series B Apical piece = 30 mm. Basal piece = 10 mm. 



We took two series of twenty stems each; in series A the shorter 

 piece of 10 mm. was the apical one and the longer of 20 mm. was 

 the basal one; while in series B, on the contrary, the shorter 

 piece was the basal one and the longer the apical one. The 

 averages are in series A: for the apical piece (10 mm.) 65.4 hours, 

 and for the basal piece (20 mm.) 64.2 hours; in series B: for the 

 apical piece (20 mm.) 69.0, and for the basal piece (10 mm.) 

 70.3 hours. The oral hydranth of the larger piece emerges about 

 an hour earlier than that of the smaller pieces, a diiference that 



