1863.] MARINE ALGM FOUND AT BRIGHTON. 515 



Geographical distribution. Mediterranean. 



Description. Root a small disk. Frond 2 to 5^ inches long ; 

 about half a line wide; irregularly much-branched. Principal 

 brutiches widely spreading, especially in the specimens bearing 

 ceraraidia, where they are almost at right angles with the main 

 stem ; axils spreading. The lower part of the stem naked. The 

 lesser branches, which are numerous, are set throughout with 

 whorls at intervals of about two diameters of the branches, with 

 very slender, soft, many times dichotomous ramuli, tapering to 

 a fine point; the tips of the branches are crowded. Articulations 

 of ramuli 4 to 6 times as long as broad. Ceramidia sessile, with 

 a narrow cylindrical neck (shorter than in D. arhuscula, but of 

 the same shape), spores densely crowded in a spherical mass. 

 Stichidia very numerous, borne on the ramuli, narrow, lanceo- 

 late, gradually tapering from the middle to an acute apex, straight 

 or gracefully curved, marked with transverse bands at short in- 

 tervals. Tetraspores numerous, dark-red, contained in the upper 

 divisions of the stichidia. Colour a rosy red, frequently varied 

 with more or less of a brownish-yellow tint. Stems brownish. 

 Substance tender and gelatinous. 



Remarks. In the for?7i of the branches the plant is nearer to 

 D. arbuscula than any other British species ; but it is a larger 

 plant. In specimens bearing ceramidia, the branches are more 

 divaricating than in those with stichidia. The ramuli, which are 

 softer and more flaccid than in any other British species of 

 Dastja, are nearer in their form and mode of growth to those 

 of D, ocellata. The stichidia also resemble in form those of 

 D. ocellata. They are very numerous. Ceramidia are also nu- 

 merous, but much less so than stichidia ; they are sessile, with 

 a narrow cylindrical neck, which is shorter than in D. arbus- 

 cula, although of the same shape. The spores seem to be ripe 

 early in August ; in some of my specimens it may be seen that 

 the drying process has caused them to be discharged from the 

 neck of the capsule. 



The plant has not yet been found growing in this country. 

 My specimens, consisting of single fronds, were found floating 

 near the shore at low water. Altogether I must have found 

 from ten to twelve specimens. 



Dr. Harvey states that our plant difiers from D. punicea in the 

 length of the articulations of the ramuli, which in the latter are 



