63 



shape chai'acteristic of the first type of cell division at 

 other points in the life history (see p , 2.5 ), it may be 

 infei-red tliat they are formed by the in^rov/th of a ring of 

 cellulose (p. 27^ ), such as is formed in the divisions of 

 the cells of Cladophora. From trie tv/o divisions, a small 

 obovate 3-celled sporeling results, which consists of a 

 sma.ller somewhat pointed basal cell, and t./o larger rounded 

 cells towards the apex, the tliree cells lying in a rov/ 

 (fig. 165), At this stage, the ciiromatophores and proto- 

 plasm are so closely packed in the peripheral portion of 

 the cytoplasm that the sporeling appears dense and opaque. 

 The pointed end of the basal cell is filled only with ho- 

 mogeneous protoplasm, sttirch grains and chromatophores be- 

 ing absent from this region (fig. 162). Intercellular 

 connections were not deiaonstrtited in the small 3-celled 

 sporelings, though tliey are apparent after the enlarge.'aont 

 of the cells. 



The description tjiven above applies to the r.uijority 

 of sporelings examined. Kany sporelings^ however, show va- 

 riations from the type described. For instance, it happens 

 rather frequently that cell division occurs after the for- 

 ras,tion of only four nuclei (fig. 161), wid before the 

 sporeling assumes the elongated shape represented in fig. 

 159. 



