DEDIFFERENTIATION IN PEROPHORA 653 
and resorption will probably be found to occur also in other 
colonial organisms, the zooids of which are united by relatively 
undifferentiated portions. 
When the stolon is resorbed in Perophora a similar process 
appears to be at work. It is further probable that in many 
other cases of resorption of subordinate organs, and of grafted 
tissues, a combination of dedifferentiation and resorption is 
also taking place, although in many higher organisms the factor 
of phagocytosis also enters, but probably often as a secondary 
phenomenon. 
3. EXPERIMENTS WITH PotasstuM CYANIDE. 
The next step was to find out something as to the factors 
involved in the reversal of dominance and the initiation of 
resorption. With this end in view some experiments with 
dilute solutions of KCN were made. IJ have to thank Professor 
Child for advice. 
As a preliminary the effect of an n/250 solution of KCN 
in sea-water was tested. It was found that this affected the 
whole system, zooid and stolon alike. Shrinkage of all parts 
took place, and death-changes were in progress after twenty-four 
hours. A series of solutions was therefore prepared as follows : 
n/250, n/500, n/1,000, and so on to n/64,000, together 
with a control vessel. All vessels were protected as far as 
possible from evaporation, and the solutions changed every 
twenty-four hours. 
The detailed results are to be found in Table I. They may 
be summarized as follows: Solutions of n/1,000 and higher 
concentration affect both stolon and zooid very adversely, 
and lead to death in about forty-eight hours. The ciliary 
action of the gills is much slowed down, and the action of the 
heart badly affected. Almost always the stolons become 
contracted and opaque. The zooids were never drained com- 
pletely by resorption; they usually shrank slightly, became 
opaque, and then died. In one or two cases the appearances 
were very similar to those seen in the dedifferentiation of 
Clavellina. Jn solutions from n/2,000 to n/8,000 inclusive 
NO. 260 x 
