MYRIONEMA. 51 



7. E. velutina, Grev. ; spreading in thin, indefinite, vel- 

 vety patches ; filaments very minute, equal in diameter 

 throughout, dissepiments slightly contracted; articulations 

 as long as or rather longer than broad ; spores elliptical, pe- 

 dicellate. Harv. Phyc. Brit. t. xxviii. B. Sphacelaria velu- 

 tina, Grev. Crypt, t. 350 ; Harv. I. c. p. 325. 



Parasitical on the thongs of Him. lorea, frequent ; also on Fucus serratus, 

 fide Greville. Annual. Summer. It often accompanies the last species, 

 to which it is closely allied. 



VI. MYRIONEMA. Grev. [Plate 10, E.] 



Minute parasites, consisting of a mass of short, erect, 

 simple jointed filaments, which spring from a thin expansion 

 formed of decumbent, cohering filaments, spreading in patches 

 on the surface of other Algae. Spores oblong, affixed either 

 to the erect or to the decumbent filaments. Name, (^10$, 

 numberless, and vy/uz, a thread. 



1 . M. strangulans, Grev. ; patches convex, confluent,brown, 

 vertical filaments clavate, densely set, spores obovoid, on 

 short stalks, attached to the decumbent filaments. Grev. 

 Crypt, t. 300 ; Hook. Br. FL ii. p. 391 ; Harv. Phyc. Brit. t. 



Parasitical on Ulvae and Enteromorphte. Annual. Summer. Forming 

 a small, dark brown, dot-like patch on the flat frond of the Ulva, or a ring- 

 like collar round the branches of Enter omorpha. 



2. M. Leclancherii, Chauv. ; patches orbicular, thin and 

 with few vertical filaments towards the edges, convex with 

 crowded filaments in the centre ; vertical filaments cylin- 

 drical ; spores on long stalks, attached to the decumbent 

 filaments. Harv. Phyc. Brit. t. xli. A. 



On decaying fronds of Rhodymenia palmata ; also on Ulva latissima in 

 deep water. Annual. Summer and autumn. Patches from a line to a 

 quarter inch in diameter, at first appearing like a thin expansion, very si- 

 milar to a Coleocluete ; at length, from the growth of the vertical filaments, 

 becoming convex. 



3. M. punctiforme, Lyngb. ; patches globose ; filaments 

 tapering to the base ; spores linear-obovate, affixed to the 

 vertical filaments, near the base. Harv. Phyc. Brit. t. xli. 

 B.; Hook. I.e. p. 391. 



Parasitical on Ceramium rubrum, Chylocladia clavellosa, &c. Patches 

 very minute, at first flat, then globose. 'Spores very narrow. 



4. M. clavatum, Carm. ; " very minute, rather convex ; 

 filaments clavate, mostly bifid; spores pedicellate, affixed to 



E2 



