156 BRITISH SEA-WEEDS. 



seed, growing on Laminaria digitata, composed of closely- 

 packed necklace-like fibres set in gelatine. Tetraspores 

 cruciate, bright scarlet. 



This tiny plant was first discovered by Mr. R. Ken- 

 nedy, at Cumbrae, in 1852, and was described by Dr. 

 Harvey in the ' Natural History Review' for 1857. 



Order XV. HELMINTHOCLADItE. 



Sosy or Purple, cylindrical, gelatinouis or gelatino-membra- 

 naeeous Sea-weeds com/posed of filaments set in loose gela- 

 tine. Spores minute, roundish, home on branching threads, 

 which radiate in a spherical firm from a central point 

 and are immersed in the frond without conceptacles ; te- 

 traspores, when present, formed in the terminal cellules of 

 the outer filaments. 



Genus LXIII. HELMINTHORA. 



Frond cylindrical, gelatinous, elastic, much branched, 

 composed of two series of filaments set in loose jelly ; 

 those in the centre, which form the axis, are parallel, longi- 

 tudinal, jointed, and decrease in size outwards ; those form- 

 ing the outer part of the frond, or periphery, are bead-like 

 and forked, and issue horizontally from the axis. Spore- 

 threads numerous, club-shaped, embedded in the outer fila- 

 ments of the fronds; tetraspores unknown. — HELMrtfTHOEA, 

 from the Grreek elmins, a worm, and thoros, a seed. 



This genus is new to collectors of British Sea- weeds. 

 It has been established by Professor Agardh, and adopted 

 by Dr. Harvey for the reception of what was formerly 

 Dudresnaia divaricata. 



