206 BRITISH SEA-WEEDS. 



len, coated with coloured cellules ; internodes transparent ; 

 those of the lower part of the stem many times as long as 

 broad, those of the minute branchlets very much shorter. 

 Spore-clusters in pairs, surrounded by long, forcipate, in- 

 volucral branchlets ; tetraspores projecting singly from the 

 nodes. 



In certain localities this species appears to be abun- 

 dant, as, for instance, near Kilkee, on the coast of Ire- 

 land, where Dr. Harvey first discovered it, in 1844, and 

 where it covered the rocks " almost to the exclusion of 

 every other species, both in places left bare at low water 

 and in the small tide-pools." Whether it be very local, 

 or whether it be frequently overlooked on account of its 

 small size, I do not know, but it is certainly considered 

 a rarity by ordinary collectors. It grows parasitic-ally 

 on small algse, is annual, and matures in autumn. It is 

 so small, delicate, and gelatinous,, that it is next to im- 

 possible to lay it out satisfactorily on paper. 



Ceramium strictum. The straight Ceramium. 



Fronds growing in dense tufts, from two to four inches 

 high, very slender, and of nearly equal diameter through- 

 out, irregularly, forkedly branched, having narrow, acute 

 axils ; branches and branchlets erect and straight ; tips 

 forcipate, and slightly hooked; nodes somewhat swollen, 

 coated with minute, purple cellules, either quite smooth or 

 clothed with long, transparent fibres ; internodes three or 

 four times as long as broad, transparent. Spore-clusters in 

 the axils of the upper branches, embraced by a few short, 

 involucral branchlets ; tetraspores prominent, whorled round 

 the nodes in the upper divisions of the branches. 



The long, transparent fibres which clothe the nodes of 



