310 Marine Algce of Berwick-on-Tweed. 



ERYTHROTRICHIA, Aresch. 



Erythrotrichia ceramicola (Lyngb.) Aresch. 



Phyc. Scand., p. 210. — Conferva ceramicola, Lyngb., Hydr. 

 Dan., p. 114, t. 48, D. 

 Deacr. Bangia ceramicola, Harv., Phyc. Brit. 

 Fig. Erythrotrichia ceramicola, Le Jol., Liste des Alg. Mar. Cherb., pi. 



in., fig. 1, 2. 

 Exsicc. Bangia ceramicola, Holmes, Alg. Brit. Rar., no. 52. 

 Syn. ,, ,, Chauv., Rech. sur 1' organ, d' Alg., p. 29 ; 



Sarv., Phyc. Brit., pi. 317 ; Hauck, Meeresalg., p. 22. 

 Hab. Epiphytic on Algae near low-water mark. Summer and Autumn. 



Berwick Bay, Scremerston. 

 When examining specimens of the smaller filamentous Algse 

 under the microscope one often meets with a few filaments of 

 this species. It is, however, very rarely found in sufficient 

 quantity to make herbarium specimens. 



Family— S quamariaceae. 

 PE^SSONNELIA, Decaisne. 



Peyssonnelia Dubyi, Crouan, 



Ann. Sc. Nat., (1844) p. 368, pi. 11b. 

 Descr. Peysonnelia Dubyi, Crouan, I.e.; Harv., Phyc. Brit. 

 Fig. „ ,, Crouan, Fl. Finist., pi. 19, fig. 130 (lower 



figure) ; Harv., Phyc. Brit., pi. 71. 

 Exsicc. „ ,, Crouan, Alg. Mar. Finist., no. 236. 



Syn. ,, ,, J. Ag., Spec. Alg. u., p. 501 ; /. Ag., Epicr., 



p. 384; Ktz., Spec. Alg. 

 Hab. On rocks, stones, and shells from half-tide level to low-water 

 mark. Also on the roots of Laminaria hyperborea. All the 

 year. Fruit Jan. — June. Not uncommon. Berwick Bay, Rocks 

 north of Dodd's Well, near the Coves, and elsewhere along the 

 coast. 

 This interesting species is often to be found on the calcareous 

 incrustations formed by Lithothamnion polymorphum near low- 

 water mark, and on the roots of Laminaria hyperborea.* The 

 fronds are orbicular or lobed, dark reddish brown or purplish, 



* I have never noticed this species on the ste?ns of Laminarice, its place 

 being taken by Petrocelis Hennedyi. 



