202 SEA-WEEDS ON 



turn, exquisite plants for microscopic study, are also 

 scattered about in the lowest levels, though not often 

 uncovered ; and the fissures which penetrate the stone 

 are well fringed with Lelesseria alata, Dasya coccinea, 

 Chylocladia articulata, Ptilota plumosa, and other 

 shade-loving species, that grow in dense mossy tufts. 

 The only living specimen that I found at Weymouth 

 of Delesseria sanguinea, was growing in one of these 

 clefts, where, also, small and brightly-coloured speci- 

 mens of Phyllophora ruhens occur ; — a plant which 

 is obtained much more abundantly, and of far greater 

 dimensions, by the dredge. This is an Alga of much 

 value for the Aquarium. It is elegant in form and 

 colour ; it bears confinement perfectly, and throws off 

 a large quantity of oxygen ; besides which it is 

 almost always studded with multitudes of parasitic 

 animals, particularly the smaller Zoophytes, and the 

 branching Bryozoa. 



The higher clefts in this vicinity produce Godium 

 tomentosum, rather a rare plant here, which I value be- 

 cause upon it, as on a pasture, T almost always find a 

 lovely little mollusk resembling the Nudibranchs, 

 — Acteon viridis, — whose green coat is spangled over 

 with most lustrous specks of blue and green, as if it 

 were powdered with gems. This plant is useful though 

 not elegant, as it affords a favourite food, not only to 

 this but to other species of phytivorous Mollusks, and 

 it will survive well in a confined vessel of sea-water. 



Griffithsia setacea, which I have mentioned above, is 

 a beautiful inhabitant of an Aquarium, and one which 

 thrives in confinement. Professor Harvey speaks of 

 the ease with which it is domesticated (Phycol. Brit. 



