( 196 ) 



It forms roundish or hemispherical cushion-like tufts on sand-covered 

 rocks, near low-water mark. 



This and the following species form a very curious little group^ 

 remarkable for their small size, and in most of the species for the 

 simplicity of the ramification. No favella^, so far as we are aware, have 

 been observed on any of them. 



4 ^2, 



CALLITHAMNION FLOMDULUM. 



EXPLANATION OF DISSECTIONS, &c. 



Fig. 1. — Callithamnion JloriduluTn, natural size. 

 2. — Filament with tetraspores. 

 3. — Tetraspores from same. 

 4. — A tetraspore. All magnified. 



