Sept. min.i THE OERMINATION AND DEVELOPMENT. i75 



found later that the sporelings germinated in the A beaker were 

 mostly smaller in size than those in the B beaker ; and in the 

 stages of development, the former were about one week behind 

 the latter. This may be due to the lower temperature of the 

 wat^^r, or to the material having been taken from the fronds 

 left in the laboratory- for five daj's. There lacks a control to 

 determine the cause. 



The following descriptions of the development of the 

 sporelings are of the material from the B beaker. 



The spores actively swimming about in the beaker soon 

 aggregate themselves in the lighted side of the apparatus. They 

 cast off the flagella before long, become spherical, and sink down 

 to the bottom. On the bottom of the lighted side of the 

 beaker thej^ are in heaps of several layers but in the other 

 parts isolatedly dispersed. These spherical resting spores are 

 coated with a *thin, cellulose membrane, the eye-spots and 

 chromoplasts remaining as in the swarming stage. The 

 solitary spores on the bottom adhere to the glass surface by a 

 gelatinous matter which is wndoubtedly secreted from the 

 spores. The spores coming in contact in heaps stick to each 

 other by the same matrix, often forming an aggregation of a 

 considerable number of cells. Pipetting out a speck of the 

 spore-aggregation and observing it under the microscope, we 

 ■find the spores not separable by a light pressure added on the 

 cover-glass. This evidences that their mutual adherence is pretty 

 firm and hence the heap of the resting spores ma\^ be compared 

 with the Palmella-stage of certain green alga (Fig. 3). 



It is to be questioned, however, whether the spores 

 aggregate themselves in nature in the same manner as in the 

 artificial culture. The heliotaxic swarmspores oi Phyllitis, which 

 habitualh^ grow on the exposed coast, will hardly find a chance 

 to stick together. We meet very frec|uentl3% late in spring, with 

 green or brown " blooming " on the sea surface by the shore 

 when the wind blows in continuoush' for several days ; and 

 we find the " blooming " is due to an immense number of 

 swarmspores of a Chloroph^'ceae or Phaeophyceae. But if one 

 is tempted to ascribe the ca^spitose habit of the PhyUitis fronds 



