12 



Charles Zeleny. 



one with only one arm removed. Fig. 2 likewise shows the 

 increase in the rate of regeneration of the arms as we pass from 

 the individuals with a smaller disk diameter to those with a 

 medium disk diameter (about 12 mm.) which show the maximum 

 rate. Then there is a decrease in rate of regeneration until indi- 



10 



11 



12 13 



15 16 17 18 19 



10 11 12 13 14 15 16 17 IS 19 

 Disk diameters in millimeters. 



Fig. 3. 



Brittle-star, Ophioglypha lacertosa. ' Comparison of lengths of regenerated arms in Series III and IV 

 bined (three and four arms removed), dotted lines, with Series I and II combined (one and two 

 removed), unbroken lines. Upper curves, 23 days; middle curves, 33 days; lower curves, 46 days 

 after operation. The regenerated arm lengths are greater in Series III and IV than in Series I and II. 



com 

 arms 



