Fig. 184. RHODYMENIA CRIST ATA. 
Colour. A rose-red ; becoming scarlet in fresh water. ^ . 
Substance. Membranaceous. 
Character of Frond. Flat ; narrow 5 ribless ; repeatedly divided in a forked manner from the 
base. General outline fan-sba]ied or round (the figure fails to give this). Divisions 
widening upwards ; many times sub-divided ; lesser ones alternate, occasionally 
jagged at the ends. 
Measurement. British specimens rarely above an inch high. 
Ffuctification. Of two kinds. 1 . A mass of spores in little spherical dark-red capsules., half 
the size of poppy-seed ; imbedded in the upper margins. 2. Tetraspores imbedded 
in the thickened and darkened tips. 
Habitat. Orkney and Shetland Islands. Frith of Forth. Berwick-upon-Tweed, and a few 
more places in the north. Thrown ashore ; sometimes on the stems of Lam. digitata. 
Very rare indeed. 
Now Euthora cristatn. Six specimens were found at Berwick in 1853. 
Fig. 185. NITOPHYLLUM BONNEMAISONIA. 
Colour. Bright rose-red. 
Substance. Delicately membranaceous. Very thin. 
Character of Frond. A flat, ribless exjiansion, rising from a short stalk ; slit and deeply 
divided. General outline fan-shaped or round. Divisions broadly wedge-shaped ; 
about equal in length ; overlapping each other. Veins rising from the base, and 
sjireading faintly upwards. 
Measurement. From 2 to' 4 inches high, and about as broad. 
Fructification. Of two kinds. 1 . Amass of sjmres in largish round capsules, scattered over 
the surface. 2. Tetraspores in roundish groups {sori) ; scattered over the surface. 
Habitat. Orkney, Bute, Ilfracombe, Torquay, Miltown, Malbay, &c. On the stems of Lam. 
digitata. Rare. 
Fig. 186. GRATELOUPIA FILTCINA. 
Colour. Dull pinkish-purple ; discolouring green. 
Substance. Membranaceous. 
Character of Frond. Flat; narrow; tufted; wavily branched. Stems simple or once forked ; 
tapering to each end ; naked at base ; above, set with long, ojiposite or alternate, 
wide-spreading, wavy, flat branches. Branches either simple or clothed in the upper 
part with branchlets ; all tapering to each end. 
Measurement. British specimens seldom more than 2 inches high. 
Fructification, Of two kinds. 1. Spores in minute globular capsules ; immersed in the sub- 
stance of the branches. 2 . Tetraspores imbedded in the branchlets. 
Habitat. South of England, On submarine rocks at half-tide level ; frequently where a 
small streamlet runs into the sea. Very rare. 
Very like some forms of GeVuVnivi cornemn ; Imt much softer. 
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