196 SEA-WEEDS 



animals, particularly the smaller Zoophytes, and the 

 branching Bryozoa. 



The higher clefts in this vicinity produce Codium 

 tomentosum, rather a rare plant here, which I value 

 because upon it, as on a pasture, I 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. 



Griffitlisia 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 ; * 

 and my experience agrees with his. Its attachment 

 to the rock is commonly slight, and its base minute, 

 so that it is sometimes difficult to procure a firmly- 

 growing specimen ; still, however, it lives and grows, 

 though with barely sufficient base to hold the filaments 

 together. (See Plate II.) 



The surfaces of the rocks are studded between tide- 

 levels with that curious ^\2i\it Rivularia nitida; which 

 is sure to attract attention, with its little shining balls 

 of vivid green colour, like school-boys' marbles, lying 

 on little beds of vegetation that adhere to the naked 

 rock. We attempt to take them up, and find them 

 blown bladders of tender gelatinous membrane ! In 

 the early autumn this singular plant occurs in abun- 



* Phycol. Brit. p. 184. 



