THE MARINE BOTANIST. 253 



CERAMIUM FLABELLIGERUM.— FAN- 

 LIKE BRANCHED CERAMIUM. 



To the naked eye the minute prickle which 

 springs from the outer edge of each joint is not ap- 

 parent, and without microscopic examination of 

 this species, it is not very easy to distinguish it 

 from Ceramium rubrum, which it nearly resembles 

 in many respects. The colour in this is more of a 

 dark purple than a red, and exactly similar to that 

 of Polysiphonia fastigiata. The upper branches in 

 C. flabelligerum in well-grown plants are much 

 divided, and spread out in somewhat of a fan-shaped 

 manner; the filaments are finer than in C. ruhrum, 

 and the size of the full-grown tuft is never above 

 three or four inches in height. In old or imper- 

 fectly-developed plants the spines are often de- 

 ficient ; still a few may be always detected on the 

 ramuli near their tips ; the articulations are entirely 

 covered with coloured cells as in C. rubrum, but 

 they are rather larger in this species, and the articu- 



