No. 6.] REGENERATION IN ANTENNi '/.. I AY. /. 303 



In these experiments, made with pieces of different lengths, 

 and from different parts of the old stem, the results were the 

 same as before. In nearly every case roots developed from 

 both ends,, and even after these ends had been once removed. 

 The experiments extended over two or three weeks. Whether, 

 if continued longer, a stem would develop at the upper end 

 among the roots there present, I do not know, but the results 

 suffice to show that the most characteristic thing that occurs 

 is the production of roots from both ends. 



I was, therefore, not a little surprised to find in another 

 series of experiments that a different result occurred. I 

 placed in an aquarium a number of pieces of Antennularia 

 that remained attached to the stones on which they had been 

 found growing. Most of the pieces stood up vertically from 

 the floor of the aquarium with the apical end upwards ; a few 

 pieces I suspended in an inverted position, i.e., with the apical 

 end downwards and the attached basal end upwards. In the 

 former cases the apical ends did not produce roots at all, but 

 a new stem. In the latter cases, in which the pieces were 

 inverted, the apical end produced neither roots nor stem. 

 Although these pieces were observed for only ten days, the 

 time is ample to show that the pieces behave differently from 

 pieces with two cut ends. I regret that I could not carry 

 these experiments further. 



One other result should be described, since it seems to have 

 a direct bearing on the last experiment. In one case a very 

 small piece had sunk to the bottom of a dish of water, where 

 it stood with its basal end in contact with the glass. It lay 

 there undisturbed, and attached itself at its basal end by means 

 of new roots. TJie apical end produced a shoot. This result, 

 taken in connection with the preceding experiment, seems to 

 indicate that the development, or the presence of roots on 

 the basal end, prevents the development of roots on the 

 apical end. This result, if it prove constant, opens the way 

 for several interesting experiments that so obviously suggest 

 themselves as to require no further mention. 



A few experiments were made with a rotating wheel con- 

 structed for the purpose. The wheel consisted of two parallel 



