490 Mr. P. H. Gosse on the Growth of Sea- Weeds. 



On the 14th the lens had detected, springing parasitically from 

 a frond of Grucilaria, a very minute filament of a Ceramium, just 

 discernible. Its tip was simply pointed ; but on the 1 7th this 

 had divided into two incurvated hooks, which on the 21st had 

 increased so as to be visible with the naked eye. 



A plant of Chondrus crispus, the firm fleshy variety, showed 

 the extremities of its old fronds plump, somewhat swollen, and 

 of a tender cherry-red hue ; while from the base new minute 

 fronds were springing. The latter on the 21st had doubled their 

 length. This plant has been in my possession all the winter. 



So also has a fine specimen oi Rhodymenia jubata, dredged in 

 Weymouth Harbour last November. It consists of numerous 

 ribbon-like fronds, much fringed at the luargins. Their original 

 red hue had become much discoloured in the course of the winter, 

 partly by decay, partly by the growth of minute fungoid Algae, 

 and partly by the deposition of the spores from Ulvce, &c., which 

 adhered, like a green dust, to them. The fx-onds had curled upon 

 themselves a good deal, and I was often on the point of throwing 

 away the plant, as a worthless incumbrance. I was much pleased 

 therefore to see signs of vigour here, and those more unequivocal 

 than in any other species I had examined. On the surface of 

 the fronds and along their edges new ciliary filaments were 

 sprouting, but most numerously at the tips of the branchlets, 

 and of the fronds themselves. From some of these extremities, 

 which were attenuated to a slender point, the " cilia " were 

 shooting in close-set array, half a dozen or more springing from 

 the same point, radiating and crossing each other in all direc- 

 tions, a perfect maze of tiny spines. At first the individual cilia 

 in these groups were less than a line in length ; but they speedily 

 increased both in length and numbei's, and were found studding 

 the ends and branchlets of all the fronds, imparting to them a 

 singular appearance. 



On the 28th (after the lapse of another week) there was no 

 longer any possibility of doubt as to the plants being in a grow- 

 ing condition. The budding points on the Gracilaria had greatly 

 increased in length, and some of them were already bifurcating ; 

 several of the shoots were now one-sixth of an inch in length, or 

 at least four times as large as they had been when first measured 

 a fortnight before. 



The furcate points of the Ceramium, the basal shoots of the 

 Chondrus, and the cilia of the Rhodymenia, had all likewise mani- 

 fested similar increase. 



On the same day (the 28th of April) I marked some minute 

 scales of the Corallina officinalis, in its incrusting stage ; which 

 from the freshness and plumpness of their edges, especially of 

 the more prominent papillae, seemed to be in a growing state. 



