Ser. Melanosperme.e. Fam. C/iordariea. 



Plate CCCXLVIII. 



MYRIONEMA CLAVATUM, Carm. (s P .) 



Gen. Char. Minute parasites, consisting of a mass of short, erect, simple, 

 jointed filaments, which spring from a thin expansion formed of de- 

 cumbent, cohering filaments, spreading in patches on the surface of 

 other Algae. Spores oblong, affixed either to the erect or to the de- 

 cumbent filaments. Myrionema (Grev.), — from fivpios, numberless, 

 and vT]fxa f a thread. 



Myrionema clavatum ; " very minute, rather convex ; filaments clavate, 

 mostly bifid ; spores obovate, pedicellate, affixed to the filaments." 



Myrionema clavatum, Harv. in Hook. Br. Fl. vol. ii. p. 391. Harv. Man. 

 ed. 2. p. 51. Kiitz. Sp. Alg. p. 540. 



Linckia clavata, Carm. Alg. App. ined. cum Ic. 



Hab. On a thin purple cartilaginous crust, probably a Verrucaria, which 

 covers the pebbles at the half-tide level. Autumn. Appin, Capt. 

 Carmichael, who adds, " The parasite is so much of the colour of the 

 crust, it requires a microscope to detect it." 



Of this curious little parasite I know nothing more than is 

 learned from the above short description, which, with the two 

 upper figures of our plate, is copied from Capt. Carmichaers 

 manuscripts. The lower figure is added as an enlarged repre- 

 sentation of a portion of the middle figure. I am indebted to 

 the Rev. M. J. Berkeley for a sketch, copied from the original by 

 Carmichael. 



Fig. 1. Myrionema clavatum, growing on a dark-coloured crust, upon a 

 quartz pebble : — the natural size. 2. The Myrionema filaments : — magni- 

 fied. 3. A barren and fertile filament : — more highly magnified. 



