104 



Fig. 112. Galaxaura fragilis Lamk. 

 Part of the thallus. (About 1V 2 : 1). 



spherical and have rather well developed chromatophores. Finally 

 we arrive at the epidermal cells, the real assimilating ones. These 

 are short, 10 12 ju> long and 20 24^ broad, in transverse sec- 

 tion often triangular, when seen from above 5 7-gonal and 



closely united (comp. those found 

 in G. squalida, Fig. 106). They 

 contain a well developed cam- 

 panulate chromatophore with 

 long branched prolongations 

 running down along the walls 

 of the cells (Fig. 110); in the 

 middle of the chromatophore a 

 pyrenoid is present. But be- 

 sides this, the real assimilating 

 tissue, the plant possesses the 

 above mentioned assimilating 

 filaments (Fig. 109); these are 

 composed of a row of cells which 



are abuot 2 3 times as long as broad (lat. about 1518 p) and 

 have thick walls, 4 p thick. They contain a much ramified chro- 

 matophore. 



The chalk incrustation is richly developed and found through- 

 out the whole tissue. 



A specimen from the harbour of Christianssted had ap- 

 parently ripe cystocarps. These are 

 nearly spherical with an opening above. 

 The carpospores are large, oval, about 

 50 // long and 30 p broad. 



My specimens seem to agree very 

 well with the description of KJELLMAX 

 and with the original specimens from 

 St. Croix. As pointed out above with 

 regard to G. rugosa, this species is 

 nearly related to the present one; for 

 the differences between them I refer to 

 the comparative remarks given above. 

 Galaxaura squalida has been ga- 

 thered both in shallow water in more sheltered places and in 

 deeper water at a depth of about 30 meters and in more 

 open sea. 



It was found in the following localities: St. Croix: Christianssteds 

 Harbour, off Frederikssted. At the shores of this island it was also col- 



Fig. 113. Galaxaura fragilis 

 Lamk. a, epidermal cells 

 seen from above, b, fila- 

 ments from the dia- 

 phragms. (About 250 : 1). 



