Marine, Algae of Bemvick-on- Tweed. 321 



A small and imperfectly understood species, which grows in 

 scattered tufts on the stems of Laminariae. The filaments are 

 very sparingly branched, the branches alternate, erect, simple, 

 or with a few scattered, simple ramuli : the articulations twice or 

 thrice as long as broad. I have seen no fruit, and believe it to 

 be very rare. The tetraspores are said to be " sessile mostly 

 axillary." 



Rhodochorton membranaceum, Magnus. 



Bot. Ergebn. Nordseefahrt, p. 67, taf. n.. figs. 7-15. 

 Descr. et Fig. Rhocloohorton membranaceum, Mar/nun, I.e. 

 Evsicc. „ ,, Hand; and Richtcr, Fhykoth. 



Univers., no. 154. 

 Syn. „ ,, Haucl; Meeresalg., p. 69. 



Hah. In the tubes of Sertularice, and other Zoophytes. Rare. Berwick 



Bay. Fruit Jan.— March. 

 An interesting species forming a sort of membranous lining 

 to the tubes of Sertulariae. The fertile branches often project 

 through the orifices of the polype cells. 



ANT1TH AMNION (Nteg.) Tjiur. 



Antitiiamnion plumula (Ellis) Thur. 



in Le Jol, List Alg. Cherb., p. 112. — Conferva plumula, 

 Ellis, Phil. Trans., vol. 57, t. 18. 

 Descr. Callithamnion plumula, Harv., Phyc. Brit. 

 Fig. „ „ Harv., I.e. pi. 242. 



Exsicc. „ „ Wyatt, Alg. Damn., no. 138; Crouan, 



Alg. Finist., no. 129 ; Le Jol., Alg. Cherb., no. 2. 

 Syn. Callithamnion plumula, /. Ag., Spec. Alg. n., p. 29 ; Id., Epicr., 

 p. 24 ; Ktz., Spec. Alg., p. 647. 

 Ceraminm plumula, Ag., Syn., p. 62. 



Pterothamnion plumula, Ncegeli, Morph. unci Syst. Ceram., 

 p. 413. 



p. spinescens, Strom/. 



in Notarisia. Anno, in., fasc. 9, pi. 3, fig. 1. 

 Hab. Occasionally washed ashore, Berwick Bay. 

 Smaller than the typical form, the pinnae short, the pinnuke 

 crowded on the upper margins of the pinnae, and either few or 

 absent altogether from the under sides, ultimate segments ending 

 in a short spine-like point. 



Although my specimens are considerably more than " 5 mm." 

 long, they agree fairly well with Stromfelt's figure and description. 

 1 p 



