Marine Algce of Berivick-un-Tweetl. 359 



line, very brittle, crumbling and falling from the plant on which 

 they are growing as the latter contracts in drying. The surface 

 of the fronds is punctate all over with the orifices of the 

 numerous, small, immersed conceptacles ; the tetraspores are 

 zonate and four-parted. 



Subgenus— LITHOPHYLLUM, Phil. 



Melobesia Lenormakdi, Aresch. 

 in J. Ag., Spec. Alg. n., p. 514. 

 Descr. Melobesia Lenormandi, Furlow, Alg. Mar. New. Eng., p. 181. 

 Fig. „ „ Crouan, Flor. du Finist., p. 150, pi. 20, 



gen. 132. 

 Exsicc. „ Holmes, Alg. Brit. Ear., no. 87 ; Desmaz, Exsic. 



2nd ser., no. 623. 

 Syn. „ ,, Le Jol., Liste Alg. Mar. Cherb., p. 151. 



Lithophyllum Lenormandi, Sosanoff, Reck., p. 85, pi. v., fig. 16 

 and 17 ; PI. VI., fig. 1, 2, 3, and 5 ; Solms, Corall., p. 15 ; Hauck, 

 Meeresalg., p. 267. 

 Hab. On rocks between tide-marks. Not uncommon. Berwick Bay, 



Sbarper Head, Scremerston. 

 Good specimens of this species can only be obtained by 

 splitting off fragments of the rock with the plant attached, for it 

 is so closely adherent that it is almost impossible to remove it. 

 The fronds form thin, pale-purplish or rose-coloured, obscurely 

 zoned, chalky crusts of considerable size; at first nearly circular and 

 crenate or lobed, but at length indefinite in outline, owing to 

 many becoming confluent,the newer fronds overlapping the older. 

 The conceptacles are numerous, hemispherical, much flattened 

 with numerous orifices ; the tetrasposes zonate four-parted. 



LITHOTHAMNION, Phil. 



LlTHOTHAMNION POLYMORPHUM (Linn.) ArfSch. 



in J. Ag., Spec. Alg. n., p. 524. — Millepora polyniorpha, 

 Linn., Syst. Nat. i., p. 1285. 

 Descr. and Fig. Melobesia polyniorpha, Harv., Phyc. Brit., pi. 345. 

 Exsicc. Lithothamnion polymorphnm, Le Jol., Alg. Mar. Cherb., no. 11. 

 Syn. ,, ,, Farlow, Mar. Alg. New. Eng., p. 



182 ; Rosanoff, Bech., p. 69 ; Hauck, Meeresalg., p. 271 ; Le 

 Jol., Liste, p. 151. 

 Spongites polymorpha, Ktz., Spec. Alg., p. 699. 

 Millepora (Nullipora) informis, Lamarck. 

 Hah. On rocks in pools between tide-marks and in deep water. All 

 the year. Common along the whole coast. 



