MARINE FLORA OF SOMERSET. 119 



is almost exclusively on the fronds of Chondus crispus. 

 Ceramium flabelligerum, I find growing in pools at Blue 

 Anchor, and on wood-work at Minehead. Though marked 

 as " rare" in the Avorks of Dr. Harvey, I believe, from the 

 nuraber of specimens which I have received from corres- 

 pondents in different localities, that it is a species generally 

 distributed on the shores of the British Isles, but probably, 

 from its near resemblance to C. rubrum, often overlooked 

 by the collector. It may not be amiss for the guidance of 

 such, to observe, that the colour is very like that of Poly- 

 siphonia fastigiata, nor is the ramificatiun very unlike, but 

 the filaments are finer than in the latter ; microscopically it 

 may be known by the unilateral spines, which arm the outer 

 edge of the branches. These, however, are frequently 

 absent on Somerset specimens, only appearing near the 

 tips of the ramuli. In such cases the proportionale larger 

 size of the cellules and cylindrical articulations afFord the 

 best characters by which it may be discriminated from 

 C. rubrum. The opaque articulations are at once suflficient 

 to distinguish it from C. acanthonotum, a British species 

 armed with a row ofmicroscopic spines in the same manner.. 

 Ceramium Deslongchampii is found in the pools at Blue 

 Anchor, Minehead, and Bossington beach ; when well 

 grown it forms handsome tufts of a very dark purple 

 colour, the articulations are transparent, very short in the 

 ramuli, and not easily seen excepting in the main stems.. 

 Of the beautiful genus, Callithamnion, we have two ex- 

 amples, C. Borreri and C. Rothii, diminutive, though well 

 fruited specimens of the form er grow with the latter on 

 the rocks at Clevedon. When mounted in Canada Balsam 

 they form very pretty and interestiiig objects for the 

 microscope. On the mud-covered rocks at Blue Anchor, 

 C. Borreri grows in tufts of three or more inchcB in height, 



