RHODOMELACE.E. 67 



of somewhat club-shaped jointed spores, springing 

 from the base of the capsules (fig. 30) . When ripe, 

 the spores escape from a pore or hole in the end of 

 the capsules. The spores are 4-jointed, and hence 

 are called tet'raspores (rerpa, four) . 



To observe these spores, the capsules must be soaked 

 in strong vinegar for some hours, and then washed 

 with water, to dissolve the calcareous matter. 



Jdnia rubens (PL IV. figs. 7 and 8) is another 

 common and very elegant little coralline, and is of a 

 pale red colour. It differs from the last in the branches 

 being dichot'omous (S/%a, in two, ro/zo?, cutting) or 

 forked, instead of pinnate. The capsules, or ceramidia, 

 have also two short horn-like branchlets, placed one 

 on each side, near the end. 



The genus Melobesia has the frond crustaceous, i. e. 

 forming a hard crust or layer. M. polymor'pha (PL 

 IV. figs. 5 and 6) is common on shells, stones, &c. 

 The capsules (ceramidia) here form little blunt cones, 

 scattered over the crusts, and containing the tufted 

 tetraspores, as in Corallina. 



Lit ho cydtis Allman'ni (fig. 9) is very minute, and 

 not uncommon upon sea- weeds, stones, &c. It con- 

 sists of a single fan-shaped crustaceous layer of cells, 

 closely investing the body to which it is attached ; its 

 fructification is unknown. 



Leaving the family of crustaceous Floridese, we 

 shall now pass to those of softer consistence, although 

 all the marine Algae contain a considerable quantity 

 of calcareous matter. 



RHODOMELA'CE^:. In this family we have the large 

 genus Polysiphonia, in which the frond (PL IV. figs. 25 

 and 26) is filamentous, the filaments being apparently 

 jointed and longitudinally striated. The filaments 

 are composed of rings of cells (fig. 27), arranged end 

 to end, and containing dark endochrome. The ends 

 of the colourless cell- walls separating the endochromes 

 of the cells of adjacent rings produce the jointed ap- 



