THE MARINE BOTANIST. 235 



attached to the ramuli or more or less immersed 

 in the substance of the branches, scattered." 

 Harv, 



The greater proportion of the plants in this tribe 

 are remarkable for the delicate beauty of their fila- 

 ments. In Ceramium the fronds are all more or less 

 clearly articulate, in some species the whole of the 

 articulation is coated with coloured cells, in others it 

 is transparent, and the partitions alone are opaque, 

 giving a very pretty chequered appearance to the 

 frond. C. diaphanum belongs to this latter section, 

 and C. rubrum to the former; the third section, 

 Ciliatay includes species with both coloured and un- 

 coloured articulations, but whose fronds are armed 

 either with microscopic hairs or spines ; C. ciliatum 

 is an example of this section, all the species of 

 which form interesting objects for the microscope, 

 nor can their specific characters be determined 

 without its aid. Griffithsia setacea is one of the 

 commonest species of Griffithsia ; it is remarkable 

 for the bursting and crackling of the membrane 

 when first placed in fresh water ; all the species are 



