Freshwater Poltjzoon from 8. Africa. 



271 



row of hooks. After germination the float becomes much 

 paler in colour and more transparent, and sometimes, but not 

 always, the hooks drop off from the processes. When they 

 do so the appearance of the valves is considerably altered. 

 At first this changed appearance occasioned some doubt as 

 to whether a second species was not present, but daily inspec- 

 tion of individual statoblasts showed that the fact is as I 

 have just stated. Boiling the valves in weak caustic potash 

 also removes the hooks. 



Fi.^ 7. 



/K?/. ^7 



Aoy. JO 



D£c 4 



Four positions of the filrst bud, showing the accompanying degeneration 

 of the original polypide B. Zeiss obj. A, eyepiece 3. a, aunulus ; 

 6, bud ; .r, old individual. 



The young individuals newly hatched from a statoblast 

 have the power of holding on to a solid substratum by means 

 of a thickened region of the ectoderm or foot (fig. 4) . They 

 can thus offer considerable resistance to the sucking of a 

 pipette. They can also change their position relatively to 

 the valves. One individual (fig. 5) emerged from its valves, 

 remaining adherent to them only by its foot. An ectocyst is 

 shown in fig. 4, and was noticed in a number of other cases. 

 It is most probable that in those figures in which it is 



