2Q8 BY THE DEEP SEA. 



borough's, Gray's, or the splendid " Phycologia Britannica " 

 of Harvey. The general characters of the genus are : frond 

 branched, often pinnate, consisting of jointed threads, with 

 tetraspores scattered along the branches. 



Other small red seaweeds will be found, representing several 

 genera, but they require the assistance of coloured figures to 

 make descriptions interesting and useful. There is the silky 

 Ptilota, with finely divided fronds, consisting of cells alter- 

 nately filled with a pink and a transparent fluid ; the rosy red 

 Griffithsia, with thread-like fronds and clear transparent joints; 

 the forking threads of Ceramhim, their tips curled in towards 

 each other; the exquisite Plocamium, with its flat crimson, 

 hair-like branches, toothed on one side only. 



The Coralline (Corallina officinalis) grows in every pool, and 

 its stony-coated joints are well-known, though it is a shock 

 to some persons to find it classed among plants, when they 

 had long imagined it to be related to the corals of which neck- 

 laces and islands are constructed. There are, in fact, several 

 genera whose members secrete carbonate of lime, and so hide 

 their vegetable character. The coralline was, however, once 

 soft and flexible. Melobesia is equally stony, but grows in thin 

 horizontal pink and purple plates or solid masses. A little 

 weak muriatic acid will soon dissolve the lime, and reveal its 

 true character. Jania somewhat resembles Corallina, but its 

 branches are exceedingly slender, and much shorter than 

 Corallina. 



Among the larger red weeds that will attract attention at 

 low-water, is the coarse textured Halymenia ligulata, of dark 

 crimson hue, whose strap-shaped fronds support other straps 

 by very slender attachments. It is closely related to Rhody- 

 menia palmata, a very common red seaweed, that is eaten in 

 Scotland, Ireland, and on the West coast of England, under 

 the name of Dulse or Dillisk, though it is said to be a not very 

 desirable food when anything else is to be obtained. Its 

 fronds are roughly fan-shaped, consisting of a great number of 



