THE MARINE BOTANIST. 255 



hue ; the joints are transparent, but in young plants 

 the upper ones are filled with a purplish fluid, 

 which prevents the pellucid nature of the articula- 

 tion being seen until the plant is dried. The irregu- 

 larly scattered, slender ^ needle-shaped prickles which 

 surround the dissepiments form the distinguishing 

 mark in this species. Grows attached to rocks and 

 stones between, or parasitic on, various algae in 

 tide-pools. Annual. Summer and autumn. 

 Common in several places Torbay. Plymouth. 

 Falmouth. Minehead, Somerset, a few plants 

 drifted ashore during the summer of 1850, I. G. 

 Youg-hal. North and west of Ireland. 



CERAMIUM ACANTHONOTUM.-UNI- 

 LATERAL SPINED CERAMIUM. 



Grows in tufts of a very dark purple colour, 

 from two to six inches in height, much matted 

 together, tips of the ramuli rolled inwards ; ar-ticu- 

 lations pellucid, dissepiments coloured, with broadly 



