508 
3 fertile cells at most are to be found in a row. This was the 
case also with a part of the material, which I examined, but some 
of the specimens had long rows of fertile cells, as many as 25 at 
least in a continuous row (cfr. fig. 103 e, f). The chromatophore in the 
Fig. 103. Acrosiphonia albescens Kjellm. Compare text. Fig. a —f . 40:1, g . 150:1. 
specimen figured (fig.[103 g) is reticular, with many small roundish 
holes and with numerous pyrenoids, other specimens had larger 
reticular chromatophores. The hole through which the zoospores 
escape is large and has a distinctly crenated margin. The main 
branch of the different species varied in thickness from 70—100 [*. 
So far as I can see, th e Acrosiphonia Tvaillii described by Bat- 
